Showing posts with label 255. Show all posts
Showing posts with label 255. Show all posts

Wednesday, 24 April 2024

Plus or Minus Groups of Magic Tori of Order 4

This is a Complete-Torus Same-Integer Plus or Minus Operation in Order 4.

As the positive integer entries of normal magic tori, and of their displayed magic squares, are always arranged in same-sum orthogonal arrays, it would seem logical to compensate any additions or subtractions to those entries, by making corresponding subtractions or additions. How can we develop this simple observation?

Preliminary Definitions

A normal magic square is an N x N array of same-sum rows, columns and main diagonals. If the magic diagonal condition is not satisfied, the square is deemed to be semi-magic. The torus, upon which a magic or semi-magic square is displayed, can be visualised by joining the opposite edges of the magic or semi-magic square in question.

There are N x N square viewpoints on the surface of a torus of order N. A normal magic torus has N x N arrays of same-sum latitudes and longitudes, and at least one magic intersection of magic diagonals on its surface. In his paper "Conformal Tiling on a Torus" published by Bridges in 2011, John M. Sullivan shows that, on a square torus T1, 0, the diagonal grid lines “form (1, ±1) diagonals on the torus, each of which is a round (Villarceau) circle in space.”

Semi-magic tori can also have magic diagonals, but the latter can never produce the magic intersections required for magic squares, either because the magic diagonals are single or parallel, or because they do not intersect correctly. Additional information about magic and semi-magic tori, with further explanations of their diagonals, can be found in the references at the end of the enclosed paper.

In order 4, starting with any magic torus, and examining cases where half of the torus numbers are subjected to equal additions, and the other half are subjected to same-integer subtractions, we notice the following: From its initial state (which we can call 0), each magic square can be transformed by four plus or minus operations that will either produce alternative magic or semi-magic square viewpoints of the same torus, or square viewpoints of other essentially different magic or semi-magic tori. Here's a simple example of two transformations:

How basic magic tori can become partially pandiagonal by implementing a complete-torus, same-integer, plus and minus operation.
3 Magic Tori of Order 4 linked by by Complete-Torus, Same-Integer, Plus or Minus Operations

Complete-Torus, Same-Integer, Plus or Minus Groups in Order 4

Please note that, in order 4, the orthogonal totals of magic and semi-magic tori are always 34. Therefore, only the diagonal totals, which can vary, are announced here. These totals are interesting because of their symmetries, and in the example illustrated above, there are pairs of diagonals that always sum to 68 (twice the magic sum). Each of the 255 magic tori of order 4 is similarly examined, and the results are given in tables and observations at the end of the following PDF paper: "Groups of Magic Tori of Order 4 Assembled by Complete-Torus, Same-Integer, Plus or Minus Operations"



Complete-Torus, Same-Integer, Plus or Minus Groups in Orders N > 4

The same method cannot always be applied to higher even orders. A quick look at some examples from even orders N = 6, N = 8, and N = 10 shows that certain magic tori have either no solutions whatsoever, or only one that can be used in a complete-torus same-integer plus or minus matrix to produce another orthogonally magic torus. In singly-even orders, even divisors with odd quotients have to be ruled out. Each case will need to be tested, and systematic computer checks will be necessary for these higher even orders.

An adaptation is of course required for odd orders, as their odd square totals do not have even integer divisors. But partial-torus same-integer divisions produce plus or minus solutions, and there are a variety of approaches.

The following paper, entitled "Examples of Partial Groups of Magic Tori of Orders N > 4 Assembled by Complete-Torus (or Near-Complete in Odd Orders) Same-Integer, Plus or Minus Operations" shows how the method used for order 4 gives some good results in higher orders:


New Developments

Since the 9th October 2024, in order to facilitate cross-referencing, the "List of 880 Frénicle Magic Squares of Order 4" (initially published on the 14th September 2019), has been updated with the detail of the Plus or Minus Groups of Magic Tori.

Since the 14th October 2024, in order to facilitate cross-referencing, the paper entitled "137 Plus-or-Minus Groups of Magic Tori of Order 4 listed with the details of the four squares generated by each of the 880 Frénicle magic squares" is available below:



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Saturday, 14 September 2019

List of the 880 Frénicle Magic Squares of Order-4

Bernard Frénicle de Bessy was the first to determine that there were 880 essentially different magic squares of order-4, and his findings were published posthumously in the "Table Générale des Quarrez Magiques de Quatre," in 1693.
Title from "Divers ouvrages de mathematique et de physique / par Messieurs de l'Académie Royale des Sciences [M. de Frénicle ... et al.]."
Title of Frénicle's study of magic squares published in 1693

This is the first page of the Table General of Magic Squares of Order-4 by Bernard Frénicle de Bessy
The "Table Générale des Quarrez Magiques de Quatre" published in 1693

It was more than 300 years later, that it was discovered that these 880 magic squares of order-4 were displayed on 255 magic tori of order-4. At first listed by type in 2011, the 255 magic tori of order-4 were later given additional index numbers in a "Table of Fourth-Order Magic Tori" in 2012. In 2019 some of the magic tori of order-4 were found to be extra-magic, with nodal intersections of 4 or more magic lines and / or knight move magic diagonals. Other studies of the magic tori of order-4 have included sub-magic 2 x 2 squares (in 2013), magic torus complementary number patterns (in 2017), and even and odd number patterns (in 2019). Then after a gap of 5 years, the magic tori have been found to belong to 137 plus or minus groups (in 2024).

It has become increasingly important to provide an easily accessible document that recapitulates these different findings. I have therefore compiled the following "List of the 880 Frénicle Indexed Magic Squares of Order-4," with their corresponding Dudeney types and also full details of the magic tori:



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Friday, 5 October 2012

Table of Fourth-Order Magic Tori

In a previous article "255 Fourth-Order Magic Tori, and 1 Third-Order Magic Torus," the 255 fourth-order magic tori have been identified and listed by type, following the numerical order of the Frénicle index numbers of the squares displayed on each torus. Although it was useful to begin this way, the classification by type is not practical when searching for a specific torus starting with any square.

I have therefore created an additional "Table of Fourth-Order Magic Tori" in which the 255 tori are also indexed and listed in numerical order for convenient reference. This table is, in a way, a homage to Bernard Frénicle de Bessy, as each torus is represented by a normalised square. The following illustration shows an example of the normalised square that represents the magic torus index n° T4.001 (type n° : T4.05.1.02), which displays not only 2 basic magic squares (Frénicle index numbers 2 and 448), but also 14 semi-magic squares:
order-4 magic torus index n° T4.001 type N° T4.05.1.02 in normalised form
The normalised squares are not necessarily traditional magic squares. Whether magic or semi-magic, they are just standard viewpoints of each magic torus. To see the other squares that are displayed by the torus, you need to displace the viewpoint, as explained in a previous article "From the Magic Square to the Magic Torus."

To view the complete "Table of Fourth-Order Magic Tori," please note that if you click on the button that appears at the top right hand side of the pdf viewer below, a new window will open and full size pages will then be displayed, with options for zooming.



Latest Developments


Further to studies published on the 28th March 2013, this table was revised on the 14th April 2013, to take into account the sub-magic 2x2 squares that are displayed on each torus, and then again on the 28th April 2013, to integrate new subdivisions that take into account different Dudeney types.

I wish to express my thanks to Aale de Winkel who pointed out an initial inversion of T4.003 and T4.004, which have since been interchanged to respect numerical order.

255 (the number of fourth-order magic tori) is now the fourth number of the sequence A270876 "Number of magic tori of order n composed of the numbers from 1 to n^2," published by the On-Line Encyclopedia of Integer Sequences (OEIS). 

Though the representation by normalised squares may not be ideal, it does give us a good insight of the subtle permutations that engender essentially different tori. The interrelationships of these tori are explored further and illustrated in an article "Multiplicative Magic Tori." published on the 21st January 2018. This post shows that the 255 magic tori of order-4 are different multiplied states of 82 Multiplicative Magic Tori (MMT) of order-4!

Since the 20th June 2019, twenty-seven of the 255 magic tori of order-4 are shown (using classic magic square geometry) to be Extra-Magic, having a parallel magic system with nodal intersections of 4 magic lines over numbers. These intersections do not yield traditional magic squares but are very significant for magic tori which have a limitless surface with no centre! Taking these findings into consideration, 136 of the 880 Frénicle-indexed magic squares are extra-magic! And when we take knight move magic diagonals into account, 6 intersecting magic lines can sometimes occur, and the total numbers of Extra-Magic Tori rise again! Since the 13th August 2019 a new article entitled "Extra-Magic Tori and Knight Move Magic Diagonals" confirms these findings and illustrates the different cases of extra-magic line intersections.

Since the 2nd September 2019, and the publication of a new article entitled "Even and Odd Number Patterns on Magic Tori of Orders 3 and 4", the Table of Fourth-Order Magic Tori is updated to include the details of the 4 essentially different even and odd number patterns.

Since the 24th April, 2024, a new article entitled "Plus or Minus Groups of Magic Tori of Order 4" now demonstrates that the 255 magic tori of order 4 (and the 880 magic squares that these tori display) originate from 137 plus or minus groups of order 4!
 

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Sunday, 22 April 2012

A New Census of Fourth-Order Magic Squares

Since Mr Henry Ernest Dudeney's first article in "The Queen" on the 15th January 1910, (the findings of which he confirmed on the page 120 of his book "Amusements in Mathematics", in 1917), the present generally accepted census of fourth-order magic squares includes three main categories as follows:

"Nasik" (Pandiagonal) : 48 magic squares
"Semi-Nasik" (Semi-pandiagonal) : 384 magic squares
"Simple" (Basic magic) : 448 magic squares
All Types : 880 = the total number of essentially different 4th-order magic squares in Frénicle standard form.

After defining magic squares as: "in their simple form of consecutive whole numbers arranged in a square so that every column, every row, and each of the two long diagonals shall add up alike," Dudeney then characterised his three main categories of fourth-order magic squares as follows:

A "Simple" square is a "square that fulfils the simple conditions and no more."
A "Semi-Nasik" (or semi-pandiagonal) square "has the additional property that the opposite short diagonals of two cells each together sum to 34."
A "Nasik" (or pandiagonal) square is a magic square on which "all the broken diagonals sum to 34."

This census was misleading, as Dudeney implied that for all his "simple" magic squares, only the main diagonals were magic. Because this was not the case, he had erroneously categorised certain partially pandiagonal squares as "simple" magic squares: There are 88 fourth-order partially pandiagonal squares that have been neglected until now, perhaps because their magic diagonals are only singly symmetric and did not satisfy Dudeney's initial conditions for semi-pandiagonal classification...

Considering the commencement of pandiagonality to take place when at least one of a magic square's broken diagonals is magic, and wishing to clarify the classification of these squares, I propose that 88 partially pandiagonal squares (including six Dudeney types VI, VII, VIII, IX, X, and XI) should be taken into account. These squares are identified in a previous article: "255 Fourth-Order Magic Tori, and 1 Third-Order Magic Torus." For example the Frénicle index squares n° 46, 50, 337 and 545, classed "simple" by Dudeney, all share the same partially pandiagonal characteristics, displayed on the magic torus T4.108 (type n° T4.03.1.1). It is clear that these partially pandiagonal squares, with two singly symmetric broken diagonals, are essentially different when compared with their basic, or "simple," fourth-order magic square cousins:

An order-4 partially pandiagonal magic torus, with index n° T4.108, and type n°T4.03.01.

Additionally, the Frénicle index squares n° 40 and 552, classed "simple" by Dudeney, both share the same partially pandiagonal characteristics, displayed on the magic torus T4.096 (type n° T4.04.01). It is clear that these partially pandiagonal squares, with one singly symmetric broken diagonal, are essentially different when compared with their basic, or "simple," fourth-order magic square cousins:

The partially pandiagonal magic torus, with index n° T4.096 and type n° T4.04.1, has 3 magic diagonals..

Since highlighting the 255 magic tori that display the 880 Frénicle magic squares, I now propose five main categories of 4th-order magic squares as follows:

Pandiagonal ("Nasik") : 48 magic squares
Semi-pandiagonal ("Semi-Nasik") : 384 magic squares with 2 four times symmetric broken magic diagonals
Partially pandiagonal : 80 magic squares with 2 singly symmetric broken magic diagonals
Partially pandiagonal : 8 magic squares with 1 singly symmetric broken magic diagonal
Basic ("Simple") : 360 magic squares
All Types : 880 = the total number of essentially different 4th-order magic squares in Frénicle standard form.

Nevertheless, these 4th-order magic squares only offer partial glimpses of the convex or concave 2D number systems that they represent. Instead of counting the magic squares we could be reasoning otherwise, and I therefore also propose an alternative census of the 255 essentially different magic tori that display the 880 4th-order magic squares:

Pandiagional : 3 Tori Type 4.01 with 8 crossed magic diagonals producing 16 magic intersections. Each torus T4.01 is entirely covered by 16 sub-magic 2x2 squares.
The 48 pandiagonal squares that are displayed are Dudeney type I.
Semi-pandiagonal : 24 Tori Type 4.02.1 with 4 crossed magic diagonals producing 8 magic intersections. Each torus T4.02.1 is entirely covered by 12 sub-magic 2x2 squares.
The 192 semi-pandiagonal squares that are displayed are Dudeney types IV and VI
Semi-pandiagonal : 12 Tori Type 4.02.2 with 4 crossed magic diagonals producing 8 magic intersections. Each torus T4.2.2 is entirely covered by 8 sub-magic 2x2 squares.
The 96 semi-pandiagonal squares that are displayed are Dudeney type II and III.
Semi-pandiagonal : 12 Tori Type 4.02.3 with 4 crossed magic diagonals producing 8 magic intersections. Each torus T4.02.3 is entirely covered by 8 sub-magic 2x2 squares.
The 96 semi-pandiagonal squares that are displayed are Dudeney type V.
Partially pandiagonal : 6 Tori Type 4.03.1 with 4 crossed magic diagonals producing 4 magic intersections. Each torus T4.03.1 is entirely covered by 8 sub-magic 2x2 squares.
The 24 partially panpandiagonal squares that are displayed are Dudeney type VI.
Partially pandiagonal : 12 Tori Type 4.03.2 with 4 crossed magic diagonals producing 4 magic intersections. Each torus T4.03.2 is entirely covered by 8 sub-magic 2x2 squares.
The 48 partially pandiagonal squares that are displayed are Dudeney types VII and IX.
Partially pandiagonal : 2 Tori Type 4.03.3 with 4 crossed magic diagonals producing 4 magic intersections. Each torus T4.03.3 is entirely covered by 8 sub-magic 2x2 squares.
The 8 partially pandiagonal squares that are displayed are Dudeney type XI.
Partially pandiagonal : 4 Tori Type 4.04 with 3 crossed magic diagonals producing 2 magic intersection. Each torus T4.04 is entirely covered by 4 sub-magic 2x2 squares.
The 8 partially pandiagonal squares that are displayed are Dudeney types VIII and X.
Basic : 92 Tori Type 4.05.1 with 2 crossed magic diagonals producing 2 magic intersections. Each torus T4.05.1 is entirely covered by 8 sub-magic 2x2 squares.
The 184 basic magic squares that are displayed are Dudeney type VI.
Basic : 32 Tori Type 4.05.2 with 2 crossed magic diagonals producing 2 magic intersections. Each torus T4.05.2 is entirely covered by 8 sub-magic 2x2 squares.
The 64 basic magic squares that are displayed are Dudeney types VII and IX.
Basic : 4 Tori Type 4.05.3 with 2 crossed magic diagonals producing 2 magic intersections. Each torus T4.05.3 is entirely covered by 4 sub-magic 2x2 squares.
The 8 basic magic squares that are displayed are Dudeney type XII.
Basic : 52 Tori Type 4.05.4 with 2 crossed magic diagonals producing 2 magic intersections. Each torus T4.05.4 is entirely covered by 4 sub-magic 2x2 squares.
The 104 basic magic squares that are displayed are Dudeney types VIII and X.
All Types : 255 = the total number of essentially different fourth-order magic tori.

The first table below compares the magic square enumerations using the 12 Dudeney types and the 12 Magic torus types. If you click on this table, a full-size version will open in a new window, which will allow for easier reading:


A new census of 4th order magic squares, based on observations of the magic tori of order-4

The second table below recapitulates the different characteristics of the 255 fourth-order magic tori and the magic squares that they display:


Recapitulative table of the magic tori of order-4

For convenient reference, the 255 magic tori that display the 880 fourth-order magic squares are now indexed and listed in normalised square form, in the "Table of Fourth-Order Magic Tori."

For further analysis of this new fourth-order magic square census, please refer to Dwane Campbell's web site, in which he has made interesting studies of 4th-order Frénicle squares constructed from base squares, and also a comparison of the Dudeney and Walkington classifications.

I wish to express my gratitude to Walter Trump, not only for his valuable advice concerning the choice of terminology, but also for his computing skills that identified the fourth-order magic torus type 4.04, and enabled a precise count.

My thanks also go out to Miguel Angel Amela who ran a computer program that confirmed the different counts of magic diagonals on 4th-order magic squares.

I also wish to express my thanks to Harry White who kindly ran a program to check and validate my hypothesis that sub-magic 2x2 squares entirely cover each 4th-order magic torus.


New development!


Posted on the 24th April 2024, an article entitled "Plus or Minus Groups of Magic Tori of Order 4" shows The minimum number of ± groups that display all of the 255 Magic Tori of order 4 is 137, a Pythagorean prime of the form 4 k + 1, where k = 34, and 137 = 4 × 34 + 1. Though it may just be pure coincidence, we cannot help noticing that: not only 4 is the dimension of the order in question, but also that 34 is its magic sum!


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Monday, 9 January 2012

255 Fourth-Order Magic Tori, and 1 Third-Order Magic Torus

This post is a translation of the article "255 Tores Magiques d'Ordre 4, et 1 Tore Magique d'Ordre 3," first published in French on the 28th October 2011.

By rolling a square and then connecting the two ends of the cylinder, the limited surface of the square is transformed into the limitless surface of a torus. The torus permits a better visualisation of the scrolling numbers of a magic square, but with the inconvenient that certain numbers are hidden on the rear external surface and inside the ring.

Torus from rectangle
"Torus from rectangle" by Lucas Vieira [Public domain], via Wikimedia Commons

In order to optimise the visualisation of the scrolling effect we can take a new flattened look. When extending a repetition of the lines, columns and diagonals of a pandiagonal magic square we obtain a grid of numbers. On this grid, starting from the initial pandiagonal square (coloured black) it is possible to generate several other different squares that are all pandiagonal:

extrapolated panmagic square of order 4

All the pandiagonal squares that are created this way can exist in a zone of seven by seven squares, (here indicated by the dotted enclosure), beyond which the squares become redundant because of the scrolling phenomenon. Beginning with an N-order pandiagonal square the number of different squares that exist in the system is N².

Convinced by the interest of this approach I chose to study the « Table générale des quarrez magiques de quatre » established by Bernard Frénicle de Bessy and published posthumously in 1693 in his book « Des quarrez magiques ». The census of these 880 4x4 squares is given in the appendix to the book « New Recreations With Magic Squares » by William H. Benson and Oswald Jacoby (Edition 1976) and also on the website of the late Harvey D. Heinz:  Frénicle n° 1 à 200, Frénicle n° 201 à 400, Frénicle n° 401 à 600, Frénicle n° 601 à 880.

Thanks to the computing skills of Walter Trump the amended and extended results of this research now reveal the existence of 255 fourth-order magic tori and 4 038 fourth-order semi-magic tori:

Fourth-order Magic Tori 

 

T4.01 Pandiagonal or Panmagic Tori Type 1

with 8 crossed magic diagonals producing 16 magic intersections.
Each torus type 1 is entirely covered by 16 sub-magic 2x2 squares.
All of the displayed pandiagonal squares are Dudeney type I. 

Panmagic torus order 4 schema of magic diagonals
16 pandiagonal squares Frénicle N°102, 104, 174, 201, 279, 281, 365, 393, 473, 530, 565, 623, 690, 748, 785 and 828. The torus is entirely covered by 16 sub-magic 2x2 squares.

order 4 pandiagonal magic torus index T4.194 type T4.01.1
The illustration below shows a way to spot the similar number sequences in different Frenicle squares showing that they come from a same torus:

order 4 pandiagonal magic torus T4.01.1 vectors
For more details of how to find a magic torus, please refer to the article "From the Magic Square to the Magic Torus".  Also, the "Table of Fourth-Order Magic Tori" shows how to convert any fourth-order magic square to normalised torus form, and thus discover the index number and complete details of the corresponding magic torus.

order 4 pandiagonal magic torus type T4.01 sub-magic 2x2 squares
16 pandiagonal squares Frénicle N°107, 109, 171, 204, 292, 294, 355, 396, 469, 532, 560, 621, 691, 744, 788, and 839. The torus is entirely covered by 16 sub-magic 2x2 squares.

order 4 pandiagonal magic torus index T4.198 type T4.01.2
16 pandiagonal squares Frénicle N°116, 117, 177, 178, 304, 305, 372, 375, 483, 485, 536, 537, 646, 647, 702 and 704. The torus is entirely covered by 16 sub-magic 2x2 squares.

order 4 pandiagonal magic torus type T4.01.3

Total   : 3 pandiagonal or panmagic tori type 1 that display 48 pandiagonal or panmagic squares, and 48 sub-magic 2x2 squares.
All of the displayed pandiagonal squares are Dudeney type I.


T4.02 Semi-pandiagonal Tori Type 2

with 4 crossed magic diagonals producing 8 magic intersections.
Each torus type 2.1 is entirely covered by 12 sub-magic 2x2 squares
Each torus type 2.2 is entirely covered by 8 sub-magic 2x2 squares
Each torus type 2.3 is entirely covered by 8 sub-magic 2x2 squares 

order 4 semi-pandiagonal magic torus diagonals


order 4 semi-pandiagonal magic torus index T4.038 type T4.02.1.01

T4.02.1 Semi-pandiagonal Tori Type 2.1

with 4 crossed magic diagonals producing 8 magic intersections. 
Each torus type 2.1 is entirely covered by 12 sub-magic 2x2 squares.
Half of the displayed semi-pandiagonal squares are Dudeney type IV and the other half are Dudeney type VI.

order 4 semi-pandiagonal magic torus type T4.02.1 sub-magic 2x2 squares
T4.02.1.01 (index n° T4.038):
8 semi-pandiagonal squares Frénicle N° 16, 160, 224, 385, 435, 603, 810, and 855, and also 8 semi-magic squares. The torus is entirely covered by 12 sub-magic 2x2 squares.

T4.02.1.02 (index n° T4.027):
8 semi-pandiagonal squares Frénicle N° 17, 85, 225, 322, 436, 604, 778, and 843, and also 8 semi-magic squares. The torus is entirely covered by 12 sub-magic 2x2 squares.

T4.02.1.03 (index n° T4.036):
8 semi-pandiagonal squares Frénicle N° 18, 141, 226, 334, 432, 599, 809, and 854, and also 8 semi-magic squares. The torus is entirely covered by 12 sub-magic 2x2 squares.

T4.02.1.04 (index n° T4.023):
8 semi-pandiagonal squares Frénicle N° 19, 61, 227, 251, 433, 600, 766, and 817, and also 8 semi-magic squares. The torus is entirely covered by 12 sub-magic 2x2 squares.

T4.02.1.05 (index n° T4.053):
8 semi-pandiagonal squares Frénicle N° 24, 137, 216, 342 443, 589, 806, and 859, and also 8 semi-magic squares. The torus is entirely covered by 12 sub-magic 2x2 squares.

T4.02.1.06 (index n° T4.044):
8 semi-pandiagonal squares Frénicle N° 25, 55, 217, 262, 444, 590, 761, and 822, and also 8 semi-magic squares. The torus is entirely covered by 12 sub-magic 2x2 squares.

T4.02.1.07 (index n° T4.073):
8 semi-pandiagonal squares Frénicle N° 30, 155, 236, 380, 419, 581, 802, and 851, and also 8 semi-magic squares. The torus is entirely covered by 12 sub-magic 2x2 squares.

T4.02.1.08 (index n° T4.064):
8 semi-pandiagonal squares Frénicle N° 31, 77, 237, 313, 420, 582, 771, and 840, and also 8 semi-magic squares. The torus is entirely covered by 12 sub-magic 2x2 squares.

T4.02.1.09 (index n° T4.115):
8 semi-pandiagonal squares Frénicle N° 48, 192, 255, 400, 570, 734, 763, and 824, and also 8 semi-magic squares. The torus is entirely covered by 12 sub-magic 2x2 squares.

T4.02.1.10 (index n° T4.101):
8 semi-pandiagonal squares Frénicle N° 49, 93, 256, 326, 467, 498, 664, and 670, and also 8 semi-magic squares. The torus is entirely covered by 12 sub-magic 2x2 squares.

T4.02.1.11 (index n° T4.111):
8 semi-pandiagonal squares Frénicle N° 54, 140, 261, 333, 499, 548, 671, and 715, and also 8 semi-magic squares. The torus is entirely covered by 12 sub-magic 2x2 squares.

T4.02.1.12 (index n° T4.125):
8 semi-pandiagonal squares Frénicle N° 60, 136, 250, 341, 504, 543, 669, and 716, and also 8 semi-magic squares. The torus is entirely covered by 12 sub-magic 2x2 squares.

T4.02.1.13 (index n° T4.138):
8 semi-pandiagonal squares Frénicle N° 64, 184, 273, 378, 507, 534, 681, and 696, and also 8 semi-magic squares. The torus is entirely covered by 12 sub-magic 2x2 squares.

T4.02.1.14 (index n° T4.130):
8 semi-pandiagonal squares Frénicle N° 65, 74, 274, 311, 456, 508, 651, and 682, and also 8 semi-magic squares. The torus is entirely covered by 12 sub-magic 2x2 squares.

T4.02.1.15 (index n° T4.155):
8 semi-pandiagonal squares Frénicle N° 73, 191, 310, 399, 572, 735, 774, and 842, and also 8 semi-magic squares. The torus is entirely covered by 12 sub-magic 2x2 squares.

T4.02.1.16 (index n° T4.151):
8 semi-pandiagonal squares Frénicle N° 76, 159, 312, 384, 459, 515, 654, and 705, and also 8 semi-magic squares. The torus is entirely covered by 12 sub-magic 2x2 squares.

T4.02.1.17 (index n° T4.165):
8 semi-pandiagonal squares Frénicle N° 84, 154, 321, 379, 451, 521, 649, and 708, and also 8 semi-magic squares. The torus is entirely covered by 12 sub-magic 2x2 squares.

T4.02.1.18 (index n° T4.175):
8 semi-pandiagonal squares Frénicle N° 92, 182, 325, 367, 466, 540, 663, and 699, and also 8 semi-magic squares. The torus is entirely covered by 12 sub-magic 2x2 squares.

T4.02.1.19 (index n° T4.201):
8 semi-pandiagonal squares Frénicle N° 110, 196, 287, 402, 566, 730, 791, and 836, and also 8 semi-magic squares. The torus is entirely covered by 12 sub-magic 2x2 squares.

T4.02.1.20 (index n° T4.204):
8 semi-pandiagonal squares Frénicle N° 111, 195, 288, 401, 569, 731, 792, and 837, and also 8 semi-magic squares. The torus is entirely covered by 12 sub-magic 2x2 squares.

T4.02.1.21 (index n° T4.220):
8 semi-pandiagonal squares Frénicle N° 119, 163, 296, 387, 488, 528, 636, and 713, and also 8 semi-magic squares. The torus is entirely covered by 12 sub-magic 2x2 squares.

T4.02.1.22 (index n° T4.224):
8 semi-pandiagonal squares Frénicle N° 121, 162, 298, 386, 490, 527, 638, and 712, and also 8 semi-magic squares. The torus is entirely covered by 12 sub-magic 2x2 squares.

T4.02.1.23 (index n° T4.226):
8 semi-pandiagonal squares Frénicle N° 123, 147, 307, 351, 475, 550, 630, and 723, and also 8 semi-magic squares. The torus is entirely covered by 12 sub-magic 2x2 squares.

T4.02.1.24 (index n° T4.231):
8 semi-pandiagonal squares Frénicle N° 125, 146, 309, 350, 477, 549, 633, and 722, and also 8 semi-magic squares. The torus is entirely covered by 12 sub-magic 2x2 squares.

Total    : 24 semi-pandiagonal tori type 2.1 that display 192 semi-pandiagonal squares, 192 semi-magic squares, and 288 sub-magic 2x2 squares
Half of the displayed semi-pandiagonal squares are Dudeney type IV and the other half are Dudeney type VI.

T4.02.2 Semi-pandiagonal Tori Type 2.2

with 4 crossed magic diagonals producing 8 magic intersections.
Each torus type 2.2 is entirely covered by 8 sub-magic 2x2 squares.
Half of the displayed semi-pandiagonal squares are Dudeney type II and the other half are Dudeney type III (associated or self-complementary squares). 

order 4 semi-pandiagonal magic torus type T4.02.2 sub-magic 2x2 squares
T4.02.2.01 (index n° T4.059):
8 semi-pandiagonal squares Frénicle N° 21, 176, 213, 361, 445, 591, 808, and 860, and also 8 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.02.2.02 (index n° T4.048):
8 semi-pandiagonal squares Frénicle N° 22, 113, 214, 290, 446, 592, 790, and 835, and also 8 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.02.2.03 (index n° T4.077):
8 semi-pandiagonal squares Frénicle N° 27, 175 (the Dürer square), 233, 360, 421, 583, 803, and 850, and also 8 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.02.2.04 (index n° T4.067):
8 semi-pandiagonal squares Frénicle N° 28, 112, 234, 289, 422, 584, 789, and 834, and also 8 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.02.2.05 (index n° T4.127):
8 semi-pandiagonal squares Frénicle N° 56, 203, 246, 392, 562, 746, 768, and 818, and also 8 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.02.2.06 (index n° T4.121):
8 semi-pandiagonal squares Frénicle N° 57, 122, 247, 299, 489, 503, 637, and 668, and also 8 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.02.2.07 (index n° T4.137):
8 semi-pandiagonal squares Frénicle N° 62, 185, 269, 377, 505, 535, 678, and 695, and also 8 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.02.2.08 (index n° T4.133):
8 semi-pandiagonal squares Frénicle N° 63, 120, 270, 297, 487, 506, 635, and 679, and also 8 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.02.2.09 (index n° T4.164):
8 semi-pandiagonal squares Frénicle N° 82, 206, 316, 395, 558, 741, 779, and 844, and also 8 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.02.2.10 (index n° T4.158):
8 semi-pandiagonal squares Frénicle N° 83, 126, 308, 317, 450, 478, 632, and 648, and also 8 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.02.2.11 (index n° T4.173):
8 semi-pandiagonal squares Frénicle N° 89, 183, 323, 368, 464, 539, 661, and 698, and also 8 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.02.2.12 (index n° T4.169):
8 semi-pandiagonal squares Frénicle N° 90, 124, 306, 324, 465, 476, 628, and 662, and also 8 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

Total    : 12 semi-pandiagonal tori type 2.2 that display 96 semi-pandiagonal squares, 96 semi-magic squares, and 96 sub-magic 2x2 squares. 
Half of the displayed semi-pandiagonal squares are Dudeney type II and the other half are Dudeney type III (associated or self-complementary squares).

T4.02.3 Semi-pandiagonal Tori Type 2.3

with 4 crossed magic diagonals producing 8 magic intersections.
Each torus type 2.3 is entirely covered by 8 sub-magic 2x2 squares.
All of the displayed semi-pandiagonal squares are Dudeney type V.

order 4 semi-pandiagonal magic torus type T4.02.3 sub-magic 2x2 squares
T4.02.3.01 (index n° T4.085):
8 semi-pandiagonal squares Frénicle N° 32, 173, 228, 362, 425, 577, 798, and 853, and also 8 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.02.3.02 (index n° T4.080):
8 semi-pandiagonal squares Frénicle N° 33, 108, 229, 293, 426, 578, 787,and 838, and also 8 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.02.3.03 (index n° T4.084):
8 semi-pandiagonal squares Frénicle N° 34, 169, 230, 356, 423, 575, 797, and 852, and also 8 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.02.3.04 (index n° T4.079):
8 semi-pandiagonal squares Frénicle N° 35, 103, 231, 282, 424, 576, 784, and 827, and also 8 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.02.3.05 (index n° T4.145):
8 semi-pandiagonal squares Frénicle N° 66, 165, 264, 389, 511, 524, 674, and 710, and also 8 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.02.3.06 (index n° T4.144):
8 semi-pandiagonal squares Frénicle N° 67, 115, 265, 302, 479, 512, 640, and 675, and also 8 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.02.3.07 (index n° T4.146):
8 semi-pandiagonal squares Frénicle N° 68, 164, 266, 388, 513, 523, 676, and 709, and also 8 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.02.3.08 (index n° T4.143):
8 semi-pandiagonal squares Frénicle N° 69, 101, 267, 280, 471, 514, 622, and 677, and also 8 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.02.3.09 (index n° T4.183):
8 semi-pandiagonal squares Frénicle N° 95, 149, 328, 345, 460, 554, 657, and 721, and also 8 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.02.3.10 (index n° T4.181):
8 semi-pandiagonal squares Frénicle N° 96, 114, 301, 329, 461, 481, 642, and 658, and also 8 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.02.3.11 (index n° T4.184):
8 semi-pandiagonal squares Frénicle N° 97, 148, 330, 344, 462, 553, 659, and 720, and also 8 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.02.3.12 (index n° T4.178):
8 semi-pandiagonal squares Frénicle N° 98, 106, 291, 331, 463, 468, 620, and 660, and also 8 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

Total    : 12 semi-pandiagonal tori type 2.3 that display 96 semi-pandiagonal squares, 96 semi-magic squares, and 96 sub-magic 2x2 squares.  
All of the displayed semi-pandiagonal squares are Dudeney type V.

T4.03 Partially pandiagonal Tori Type 3

with 4 crossed magic diagonals producing 4 magic intersections and 4 non magic intersections 
Each torus type 3 is entirely covered by 8 sub-magic 2x2 squares.
Each torus type 3.1 displays partially pandiagonal squares Dudeney type VI.
Each torus type 3.2 displays partially pandiagonal squares Dudeney types VII and IX.
Each torus type 3.3 displays partially pandiagonal squares Dudeney type XI.

order 4 partially pandiagonal magic torus type 3 magic diagonals

order 4 partially pandiagonal magic torus index T4.108 type T4.03.1.1

T4.03.1 Partially pandiagonal Tori Type 3.1

with 4 crossed magic diagonals producing 4 magic intersections and 4 non magic intersections.
Each torus type 3.1 is entirely covered by 8 sub-magic 2x2 squares.
All of the displayed partially pandiagonal squares are Dudeney type VI.

order 4 partially pandiagonal magic torus type T4.03.1 sub-magic 2x2 squares
T4.03.1.1 (index n° T4.108)
4 partially pandiagonal squares Frénicle N° 46, 50, 337 and 545, and also 12 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.03.1.2 (index n° T4.174):
4 partially pandiagonal squares Frénicle N° 91, 150, 320 and 394, and also 12 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares. (see this torus here).

T4.03.1.3 (index n° T4.186)
4 partially pandiagonal squares Frénicle N° 100, 285, 617 and 793, and also 12 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.03.1.4 (index n° T4.246)
4 partially pandiagonal squares Frénicle N° 132, 253, 259 and 719, and also 12 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.03.1.5 (index n° T4.216)
4 partially pandiagonal squares Frénicle N° 179, 376, 482 and 645, and also 12 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.03.1.6 (index n° T4.168):
4 partially pandiagonal squares Frénicle N° 187, 366, 667 and 780, and also 12 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

Total    : 6 partially pandiagonal tori type 3.1 that display 24 partially pandiagonal squares, 72 semi-magic squares, and 48 sub-magic 2x2 squares.  
All of the displayed partially pandiagonal squares are Dudeney type VI.


T4.03.2 Partially pandiagonal Tori Type 3.2

with 4 crossed magic diagonals producing 4 magic intersections and 4 non magic intersections.
Each torus type 3.2 is entirely covered by 8 sub-magic 2x2 squares.
Half of the displayed partially pandiagonal squares are Dudeney type VII and the other half are Dudeney type IX.

order 4 partially pandiagonal magic torus type T4.03.2 sub-magic 2x2 squares
T4.03.2.01 (index n° T4.193):
4 partially pandiagonal squares Frénicle N° 105, 439, 442 and 786, and also 12 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.03.2.02 (index n° T4.212):
4 partially pandiagonal squares Frénicle N° 118, 271, 272 and 486, and also 12 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.03.2.03 (index n° T4.214)
4 partially pandiagonal squares Frénicle N° 180, 347, 349 and 538, and also 12 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.03.2.04 (index n° T4.188)
4 partially pandiagonal squares Frénicle N° 200, 737, 765 and 868, and also 12 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.03.2.05 (index n° T4.189)
4 partially pandiagonal squares Frénicle N° 207, 736, 775 and 831, and also 12 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.03.2.06 (index n° T4.195):
4 partially pandiagonal squares Frénicle N° 208, 525, 526 and 693, and also 12 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.03.2.07 (index n° T4.060):
4 partially pandiagonal squares Frénicle N° 283, 472, 588 and 795, and also 12 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.03.2.08 (index n° T4.141):
4 partially pandiagonal squares Frénicle N° 303, 509, 510 and 644, and also 12 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.03.2.09 (index n° T4.234):
4 partially pandiagonal squares Frénicle N° 371, 551, 552 and 701, and also 12 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.03.2.10 (index n° T4.123):
4 partially pandiagonal squares Frénicle N° 390, 571, 782 and 867, and also 12 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.03.2.11 (index n° T4.221):
4 partially pandiagonal squares Frénicle N° 407, 531, 692 and 711, and also 12 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.03.2.12 (index n° T4.161)
4 partially pandiagonal squares Frénicle N° 408, 555, 783 and 829, and also 12 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

Total    : 12 partially pandiagonal tori type 3.2 that display 48 partially pandiagonal squares, 144 semi-magic squares, and 96 sub-magic 2x2 squares.  
Half of the displayed partially pandiagonal squares are Dudeney type VII and the other half are Dudeney type IX.


T4.03.3 Partially pandiagonal Tori Type 3.3

with 4 crossed magic diagonals producing 4 magic intersections and 4 non magic intersections.
Each torus type 3.3 is entirely covered by 8 sub-magic 2x2 squares.
All of the displayed partially pandiagonal squares are Dudeney type XI.

order 4 partially pandiagonal magic torus type T4.03.3 sub-magic 2x2 squares
T4.03.3.1 (index n° T4.217):
4 partially pandiagonal squares Frénicle N° 181, 374, 484 and 643, and also 12 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.03.3.2 (index n° T4.187):
4 partially pandiagonal squares Frénicle N° 202, 364, 689 and 724, and also 12 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

Total    : 2 partially pandiagonal tori type 3.3 that display 8 partially pandiagonal squares, 24 semi-magic squares, and 16 sub-magic 2x2 squares.  
All of the displayed partially pandiagonal squares are Dudeney type XI.



T4.04 Partially pandiagonal Tori Type 4

with 3 crossed magic diagonals producing 2 magic intersections and 2 non magic intersections
Each torus type 4 is entirely covered by 4 sub-magic 2x2 squares. Half of the displayed partially pandiagonal squares are Dudeney type VIII and the other half are Dudeney type X.
(tori identified thanks to Walter Trump's computing skills)


order 4 partially pandiagonal magic tori type 4 magic diagonals

order 4 partially pandiagonal magic torus index T4.096 type T4.04.1
order 4 partially pandiagonal magic torus type T4.04 sub-magic 2x2 squares
T4.04.1 (index n° T4.096)
2 partially pandiagonal squares Frénicle N° 40 and 522, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.04.2 (index n° T4.098)
2 partially pandiagonal squares Frénicle N° 275 and 519, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.04.3 (index n° T4.120)
2 partially pandiagonal squares Frénicle N° 542 and 866, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.04.4 (index n° T4.157)
2 partially pandiagonal squares Frénicle N° 727 and 865 and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

Total    : 4 partially pandiagonal tori type 4 that display 8 partially pandiagonal squares, 56 semi-magic squares, and 16 sub-magic 2x2 squares
Half of the displayed partially pandiagonal squares are Dudeney type VIII and the other half are Dudeney type X.



T4.05 Basic Magic Tori Type 5

with 2 crossed magic diagonals producing 2 magic intersections
Each torus type 5.1 and 5.2 is entirely covered by 8 sub-magic 2x2 squares.
Each torus type 5.3 and 5.4 is entirely covered by 4 sub-magic 2x2 squares.

order 4 basic magic tori type 5 magic diagonals

order 4 basic magic torus index T4.002 type T4.05.1.1

T4.05.1 Basic Magic Tori Type 5.1

with 2 crossed magic diagonals producing 2 magic intersections. 
Each torus type 5.1 is entirely covered by 8 sub-magic 2x2 squares.
All of the displayed magic squares are Dudeney type VI.

order 4 basic magic torus type T4.05.1 sub-magic 2x2 squares
T4.05.1.01 (index n° T4.002)
2 magic squares Frénicle N° 1 and 458, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.02 (index n° T4.001)
2 magic squares Frénicle N° 2 and 448, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.03 (index n° T4.012)
2 magic squares Frénicle N° 4 and 672, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.04 (index n° T4.008)
2 magic squares Frénicle N° 5 and 625, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.05 (index n° T4.011)
2 magic squares Frénicle N° 6 and 611, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.06 (index n° T4.007)
2 magic squares Frénicle N° 7 and 612, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.07 (index n° T4.034)
2 magic squares Frénicle N° 12 and 520, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.08 (index n° T4.035)
2 magic squares Frénicle N° 13 and 339, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.09 (index n° T4.025)
2 magic squares Frénicle N° 14 and 457, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.10 (index n° T4.029)
2 magic squares Frénicle N° 15 and 258, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.11 (index n° T4.089)
2 magic squares Frénicle N° 36 and 742, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.12 (index n° T4.062)
2 magic squares Frénicle N° 37 and 832, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.13 (index n° T4.088)
2 magic squares Frénicle N° 38 and 706, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.14 (index n° T4.043)
2 magic squares Frénicle N° 39 and 826, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.
  
T4.05.1.15 (index n° T4.103):  
2 magic squares Frénicle N° 44 and 352, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.16 (index n° T4.107):
 
2 magic squares Frénicle N° 45 and 557, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.17 (index n° T4.109):
 
2 magic squares Frénicle N° 47 and 556, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.18 (index n° T4.063):  
2 magic squares Frénicle N° 51 and 772, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.19 (index n° T4.114):
 
2 magic squares Frénicle N° 52 and 222, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.20 (index n° T4.100):
 
2 magic squares Frénicle N° 53 and 223, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.21 (index n° T4.148):  
2 magic squares Frénicle N° 70 and 391, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.22 (index n° T4.149):
 
2 magic squares Frénicle N° 71 and 359, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.23 (index n° T4.132):  
2 magic squares Frénicle N° 72 and 745, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.24 (index n° T4.066):
 
2 magic squares Frénicle N° 75 and 857, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.25 (index n° T4.119):
 
2 magic squares Frénicle N° 78 and 725, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.26 (index n° T4.047):
 
2 magic squares Frénicle N° 79 and 856, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.27 (index n° T4.046):
 
2 magic squares Frénicle N° 80 and 760, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.28 (index n° T4.118):
 
2 magic squares Frénicle N° 81 and 430, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.29 (index n° T4.171):
 
2 magic squares Frénicle N° 86 and 363, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.30 (index n° T4.172):
 
2 magic squares Frénicle N° 87 and 318, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.31 (index n° T4.243)
2 magic squares Frénicle N° 127 and 220, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.
  
T4.05.1.32 (index n° T4.136):  
2 magic squares Frénicle N° 130 and 561, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.33 (index n° T4.134):
 
2 magic squares Frénicle N° 131 and 624, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.34 (index n° T4.072):
 
2 magic squares Frénicle N° 133 and 807, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.35 (index n° T4.071)
2 magic squares Frénicle N° 134 and 830, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T 4.05.1.36 (index n° T4.244):
 
2 magic squares Frénicle N° 135 and 219, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.37 (index n° T4.052):
 
2 magic squares Frénicle N° 138 and 825, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.38 (index n° T4.124):
 
2 magic squares Frénicle N° 139 and 610, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.39 (index n° T4.227):  
2 magic squares Frénicle N° 143 and 627, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.40 (index n° T4.232):
 
2 magic squares Frénicle N° 144 and 631, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.41 (index n° T4.253):  
2 magic squares Frénicle N° 151 and 286, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.42 (index n° T4.211):
 
2 magic squares Frénicle N° 152 and 454, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.43 (index n° T4.202):
 
2 magic squares Frénicle N° 153 and 447, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.44 (index n° T4.252)
2 magic squares Frénicle N° 156 and 284, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.45 (index n° T4.057):
 
2 magic squares Frénicle N° 157 and 801, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.46 (index n° T4.248):
 
2 magic squares Frénicle N° 158 and 428, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.47 (index n° T4.076):  
2 magic squares Frénicle N° 166 and 848, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.48 (index n° T4.058):
 
2 magic squares Frénicle N° 167 and 846, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.49 (index n° T4.192):
 
2 magic squares Frénicle N° 168 and 609, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.50 (index n° T4.140):  
2 magic squares Frénicle N° 186 and 683, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.51 (index n° T4.254):
 
2 magic squares Frénicle N° 188 and 295, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.52 (index n° T4.128):
 
2 magic squares Frénicle N° 189 and 533, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.53 (index n° T4.250):
 
2 magic squares Frénicle N° 190 and 474, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.54 (index n° T4.207):  
2 magic squares Frénicle N° 194 and 480, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.55 (index n° T4.129):  
2 magic squares Frénicle N° 198 and 680, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.56 (index n° T4.196):
 
2 magic squares Frénicle N° 199 and 629, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.57 (index n° T4.004):  
2 magic squares Frénicle N° 210 and 656, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.58 (index n° T4.003):
 
2 magic squares Frénicle N° 211 and 619, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.59 (index n° T4.225):  
2 magic squares Frénicle N° 218 and 707, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.60 (index n° T4.131):
 
2 magic squares Frénicle N° 221 and 653, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.61 (index n° T4.229):  
2 magic squares Frénicle N° 252 and 743, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.62 (index n° T4.247):
 
2 magic squares Frénicle N° 254 and 740, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.63 (index n° T4.065)
2 magic squares Frénicle N° 257 and 841, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.64 (index n° T4.045):  
2 magic squares Frénicle N° 314 and 821, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.65 (index n° T4.024):
 
2 magic squares Frénicle N° 315 and 597, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.66 (index n° T4.139):  
2 magic squares Frénicle N° 336 and 747, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.67 (index n° T4.074):
 
2 magic squares Frénicle N° 338 and 861, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.68 (index n° T4.150):  
2 magic squares Frénicle N° 370 and 639, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.69 (index n° T4.147):  
2 magic squares Frénicle N° 381 and 614, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.70 (index n° T4.054):
 
2 magic squares Frénicle N° 382 and 849, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.71 (index n° T4.037):
 
2 magic squares Frénicle N° 383 and 594, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.72 (index n° T4.126):
 
2 magic squares Frénicle N° 397 and 694, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.73 (index n° T4.112):
 
2 magic squares Frénicle N° 398 and 626, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.74 (index n° T4.215):  
2 magic squares Frénicle N° 404 and 641, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.75 (index n° T4.218):  
2 magic squares Frénicle N° 427 and 718, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.76 (index n° T4.102):
 
2 magic squares Frénicle N° 429 and 673, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.77 (index n° T4.223):  
2 magic squares Frénicle N° 452 and 750, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.78 (index n° T4.028):  
2 magic squares Frénicle N° 502 and 596, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.79 (index n° T4.176):
 
2 magic squares Frénicle N° 516 and 752, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.80 (index n° T4.039):  
2 magic squares Frénicle N° 547 and 593, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.81 (index n° T4.166):  
2 magic squares Frénicle N° 573 and 697, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.82 (index n° T4.152):
 
2 magic squares Frénicle N° 574 and 634, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.83 (index n° T4.041):  
2 magic squares Frénicle N° 595 and 804, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.84 (index n° T4.042):
 
2 magic squares Frénicle N° 602 and 764, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.85 (index n° T4.185):
 
2 magic squares Frénicle N° 615 and 815, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.86 (index n° T4.163)
2 magic squares Frénicle N° 665 and 777, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.87 (index n° T4.162):  
2 magic squares Frénicle N° 739 and 755, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.88 (index n° T4.167):
 
2 magic squares Frénicle N° 751 and 776, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.89 (index n° T4.200):
 
2 magic squares Frénicle N° 756 and 862, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.90 (index n° T4.203):
 
2 magic squares Frénicle N° 769 and 864, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.91 (index n° T4.113):
 
2 magic squares Frénicle N° 813 and 819, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.1.92 (index n° T4.153):
 
2 magic squares Frénicle N° 816 and 833, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

Total    : 92 basic magic tori type 5.1 that display 184 basic magic squares, 1,288 semi-magic squares, and 736 sub-magic 2x2 squares
All of the displayed basic magic squares are Dudeney type VI.

T4.05.2 Basic Magic Tori Type 5.2

with 2 crossed magic diagonals producing 2 magic intersections. 
Each torus type 5.2 is entirely covered by 8 sub-magic 2x2 squares.
Half of the displayed magic squares are Dudeney type VII and the other half are Dudeney type IX.

order 4 basic magic torus type T4.05.2 sub-magic 2x2 squares
T4.05.2.01 (index n° T4.049)
2 magic squares Frénicle N° 23 and 767, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.2.02 (index n° T4.068)
2 magic squares Frénicle N° 29 and 781, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.2.03 (index n° T4.026):  
2 magic squares Frénicle N° 59 and 870, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.2.04 (index n° T4.249):
 
2 magic squares Frénicle N° 142 and 438, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.2.05 (index n° T4.228):
 
2 magic squares Frénicle N° 145 and 529, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.2.06 (index n° T4.219):
 
2 magic squares Frénicle N° 161 and 703, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.2.07 (index n° T4.040):  
2 magic squares Frénicle N° 172 and 869, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.2.08 (index n° T4.255):
 
2 magic squares Frénicle N° 193 and 268, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.2.09 (index n° T4.206):
 
2 magic squares Frénicle N° 197 and 346, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.2.10 (index n° T4.197):
 
2 magic squares Frénicle N° 205 and 700, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.2.11 (index n° T4.122):  
2 magic squares Frénicle N° 215 and 799, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.2.12 (index n° T4.251):  
2 magic squares Frénicle N° 235 and 845, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.
  
T4.05.2.13 (index n° T4.032):  
2 magic squares Frénicle N° 249 and 878, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.2.14 (index n° T4.142)
2 magic squares Frénicle N° 300 and 559, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.2.15 (index n° T4.061):  
2 magic squares Frénicle N° 335 and 470, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.2.16 (index n° T4.199):  
2 magic squares Frénicle N° 348 and 714, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.2.17 (index n° T4.033):  
2 magic squares Frénicle N° 358 and 875, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.
 
T4.05.2.18 (index n° T4.233):
 
2 magic squares Frénicle N° 369 and 563, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.2.19 (index n° T4.209):
 
2 magic squares Frénicle N° 373 and 717, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.2.20 (index n° T4.210):
 
2 magic squares Frénicle N° 403 and 738, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.2.21 (index n° T4.205):
 
2 magic squares Frénicle N° 405 and 517, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.2.22 (index n° T4.156):
 
2 magic squares Frénicle N° 406 and 453, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.2.23 (index n° T4.160):  
2 magic squares Frénicle N° 418 and 805, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.2.24 (index n° T4.245):  
2 magic squares Frénicle N° 441 and 873, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.2.25 (index n° T4.154):
 
2 magic squares Frénicle N° 455 and 729, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.2.26 (index n° T4.191):  
2 magic squares Frénicle N° 518 and 728, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.2.27 (index n° T4.222):
 
2 magic squares Frénicle N° 564 and 732, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.2.28 (index n° T4.230):
 
2 magic squares Frénicle N° 567 and 749, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.2.29 (index n° T4.110):
 
2 magic squares Frénicle N° 568 and 757, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.2.30 (index n° T4.075):  
2 magic squares Frénicle N° 580 and 858, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.2.31 (index n° T4.055):  
2 magic squares Frénicle N° 587 and 879, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

T4.05.2.32 (index n° T4.116):
 
2 magic squares Frénicle N° 733 and 758, and also 14 semi-magic squares. The torus is entirely covered by 8 sub-magic 2x2 squares.

Total    : 32 basic magic tori type 5.2 that display 64 basic magic squares, 448 semi-magic squares, and 256 sub-magic 2x2 squares
Half of the displayed basic magic squares are Dudeney type VII and the other half are Dudeney type IX.

T4.05.3 Basic Magic Tori Type 5.3

with 2 crossed magic diagonals producing 2 magic intersections. 
Each torus type 5.3 is entirely covered by 4 sub-magic 2x2 squares.
All of the displayed magic squares are Dudeney type XII.

order 4 basic magic torus type T4.05.3 sub-magic 2x2 squares
T4.05.3.1 (index n° T4.005)
2 magic squares Frénicle N° 3 and 613, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.3.2 (index n° T4.170):  
2 magic squares Frénicle N° 88 and 650, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.3.3 (index n° T4.006):  
2 magic squares Frénicle N° 209 and 449, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.3.4 (index n° T4.159):  
2 magic squares Frénicle N° 319 and 666, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

Total    : 4 basic magic tori type 5.3 that display 8 basic magic squares, 56 semi-magic squares, and 16 sub-magic 2x2 squares
All of the displayed basic magic squares are Dudeney type XII

T4.05.4 Basic Magic Tori Type 5.4

with 2 crossed magic diagonals producing 2 magic intersections. 
Each torus type 5.4 is entirely covered by 4 sub-magic 2x2 squares.
Half of the displayed magic squares are Dudeney type VIII and the other half are Dudeney type X.

order 4 basic magic torus type T4.05.4 sub-magic 2x2 squares
T4.05.4.01 (index n° T4.019)
2 magic squares Frénicle N° 8 and 343, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.02 (index n° T4.018)
2 magic squares Frénicle N° 9 and 263, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.03 (index n° T4.022)
2 magic squares Frénicle N° 10 and 240, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.04 (index n° T4.017)
2 magic squares Frénicle N° 11 and 241, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.05 (index n° T4.050)
2 magic squares Frénicle N° 20 and 811, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.06 (index n° T4.069)
2 magic squares Frénicle N° 26 and 812, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.07 (index n° T4.097)
2 magic squares Frénicle N° 41 and 493, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.08 (index n° T4.095)
2 magic squares Frénicle N° 42 and 494, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.09 (index n° T4.092):  
2 magic squares Frénicle N° 43 and 434, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.10 (index n° T4.078):  
2 magic squares Frénicle N° 58 and 877, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.11 (index n° T4.182)
2 magic squares Frénicle N° 94 and 655, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.12 (index n° T4.177)
2 magic squares Frénicle N° 99 and 618, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.13 (index n° T4.239):
 
2 magic squares Frénicle N° 128 and 773, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.14 (index n° T4.240):
 
2 magic squares Frénicle N° 129 and 762, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.15 (index n° T4.083):
 
2 magic squares Frénicle N° 170 and 874, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.16 (index n° T4.237)
2 magic squares Frénicle N° 212 and 794, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.17 (index n° T4.242):
 
2 magic squares Frénicle N° 232 and 863, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.18 (index n° T4.020):  
2 magic squares Frénicle N° 238 and 411, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.19 (index n° T4.015):
 
2 magic squares Frénicle N° 239 and 412, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.20 (index n° T4.208):
 
2 magic squares Frénicle N° 242 and 546, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.21 (index n° T4.105):  
2 magic squares Frénicle N° 243 and 501, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.22 (index n° T4.014):
 
2 magic squares Frénicle N° 244 and 415, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.23 (index n° T4.010)
2 magic squares Frénicle N° 245 and 416, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.24 (index n° T4.082):
 
2 magic squares Frénicle N° 248 and 872, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.25 (index n° T4.016):
 
2 magic squares Frénicle N° 260 and 410, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.26 (index n° T4.099):
 
2 magic squares Frénicle N° 276 and 491, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.27 (index n° T4.086):
 
2 magic squares Frénicle N° 277 and 685, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.28 (index n° T4.031):
 
2 magic squares Frénicle N° 278 and 601, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.29 (index n° T4.179):
 
2 magic squares Frénicle N° 327 and 616, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.30 (index n° T4.180):
 
2 magic squares Frénicle N° 332 and 652, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.31 (index n° T4.021)
2 magic squares Frénicle N° 340 and 409, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.32 (index n° T4.236):
 
2 magic squares Frénicle N° 353 and 770, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.33 (index n° T4.104):
 
2 magic squares Frénicle N° 354 and 823, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.34 (index n° T4.081):
 
2 magic squares Frénicle N° 357 and 871, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.35 (index n° T4.013):
 
2 magic squares Frénicle N° 413 and 607, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.36 (index n° T4.009):
 
2 magic squares Frénicle N° 414 and 608, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.37 (index n° T4.238):
 
2 magic squares Frénicle N° 417 and 796, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.38 (index n° T4.093):
 
2 magic squares Frénicle N° 431 and 686, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.39 (index n° T4.190):
 
2 magic squares Frénicle N° 437 and 814, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.40 (index n° T4.241):
 
2 magic squares Frénicle N° 440 and 880, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.41 (index n° T4.094):
 
2 magic squares Frénicle N° 492 and 688, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.42 (index n° T4.030):
 
2 magic squares Frénicle N° 495 and 598, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.43 (index n° T4.090):
 
2 magic squares Frénicle N° 496 and 754, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.
 
T4.05.4.44 (index n° T4.087):
 
2 magic squares Frénicle N° 497 and 684, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.45 (index n° T4.106):
 
2 magic squares Frénicle N° 500 and 606, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.46 (index n° T4.235):
 
2 magic squares Frénicle N° 541 and 759, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.47 (index n° T4.135):
 
2 magic squares Frénicle N° 544 and 605, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.48 (index n° T4.070):
 
2 magic squares Frénicle N° 579 and 847, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.49 (index n° T4.056):
 
2 magic squares Frénicle N° 585 and 800, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.50 (index n° T4.051):
 
2 magic squares Frénicle N° 586 and 876, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.51 (index n° T4.091):
 
2 magic squares Frénicle N° 687 and 753, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

T4.05.4.52 (index n° T4.117):  
2 magic squares Frénicle N° 726 and 820, and also 14 semi-magic squares. The torus is entirely covered by 4 sub-magic 2x2 squares.

Total   : 52 basic magic tori type 5.4 that display 104 basic magic squares, 728 semi-magic squares, and 208 sub-magic 2x2 squares.
Half of the displayed basic magic squares are Dudeney type VIII and the other half are Dudeney type X.


Grand Totals of the 4th-Order Magic Tori :
255 FOURTH-ORDER MAGIC TORI THAT DISPLAY 880 MAGIC SQUARES,

3 200 SEMI-MAGIC SQUARES, AND 1 920 SUB-MAGIC 2x2 SQUARES


4th order magic tori recap table order 4


Fourth-order Semi-Magic Tori


A semi-magic square is a square that contains arithmetical magic in all of its rows and columns, but not in both of its main diagonals.

According to Walter Trump's first computer calculations the number of semi-magic and magic squares is 68,688. 68,688 - 880 magic squares = 67,808 semi-magic squares.
3,200 semi-magic squares are already displayed on the 255 magic tori. We can deduce that there are also 67,808 – 3,200 = 64,608 4th-order semi-magic squares displayed on another 4,038 semi-magic tori (64,608 / 16). The semi-magic tori could have crossed magic diagonals that do not produce magic intersections, parallel magic diagonals (without magic intersections), or no magic diagonals at all. Walter Trump's latest computer programme confirms that the fourth-order semi-magic tori either have parallel magic diagonals that produce no magic intersections, or no magic diagonals at all. Some examples of the different types (provisionally represented here by a single square for each torus) are shown below:

T4.06 Semi-Magic Tori Type 6

with 4 parallel magic diagonals producing no magic intersections

order 4 semi-magic torus type 6

Total   : 12 semi-magic tori type 6 that display 192 semi-magic squares
(semi-magic tori counted by Walter Trump's computer calculations)


T4.07 Semi-Magic Tori Type 7

with 2 unequally spaced parallel magic diagonals producing no magic intersections

order 4 semi-magic torus type 7

Total   : 12 semi-magic tori type 7 that display 192 semi-magic squares
(semi-magic tori counted by Walter Trump's computer calculations)


T4.08 Semi-Magic Tori Type 8

with 2 equally spaced parallel magic diagonals producing no magic intersections

order 4 semi-magic torus type 8

Total   : 88 semi-magic tori type 8 that display 1,408 semi-magic squares 
(semi-magic tori counted by Walter Trump's computer calculations)

T4.09 Semi-Magic Tori Type 9

with a single magic diagonal producing no magic intersection

order 4 semi-magic torus type T4.09

Total   : 200 semi-magic tori type 9 that display 3,200 semi-magic squares
(semi-magic tori counted by Walter Trump's computer calculations)

T4.10 Semi-Magic Tori Type 10

with no magic diagonals

order 4 semi-magic torus type 10

Total   : 3,726 semi-magic tori type 10 that display 59,616 semi-magic squares
(semi-magic tori counted by Walter Trump's computer calculations)


The study remains to be completed by listing all the semi-magic tori in numerical order (using Frénicle standard form for example).

Grand Totals of the 4th-Order Semi-Magic Tori :
4,038 FOURTH-ORDER SEMI-MAGIC TORI THAT DISPLAY
64,608 SEMI-MAGIC SQUARES

 

Magic and Semi-Magic 4th-Order Tori : Conclusions


The study of the table of 880 4th-order magic squares reveals the existence of 255 magic tori, that not only display 880 magic squares, but also 3,200 semi-magic squares. All of the 255 magic tori are entirely covered by 2x2 sub-magic squares. There is a total of 1,920 sub-magic 2x2 squares on the 255 magic tori.

The number of N-order squares (magic and semi-magic squares) that are displayed on each N-order magic torus = N². 

4,038 semi-magic 4th-order tori have also been found, and these display a further 64,608 semi-magic squares. The sub-magic 2x2 squares of the 4th-order semi-magic tori have yet to be enumerated.

255 is now the fourth number of the sequence A270876 "Number of magic tori of order n composed of the numbers from 1 to n^2," published by the On-Line Encyclopedia of Integer Sequences (OEIS).

4,293 (255 + 4,038) is now the fourth number of the sequence A271104 "Number of magic and semi-magic tori of order n composed of the numbers from 1 to n^2," published by the On-Line Encyclopedia of Integer Sequences (OEIS).


T3 Third-Order Magic Torus


The study would not be complete without examining the unique 3rd-order magic torus. Beginning with the 3x3 magic square in Frénicle standard form (at the top left of the following illustration), and taking into account the scrolling effect on the 3rd order magic torus we obtain another eight 3rd-order semi-magic squares:

order 3 basic magic torus type T3 before Frénicle standard form

After transformation of these semi-magic squares into Frénicle standard form we obtain:

order 3 basic magic torus type T3 after Frénicle standard form

The 3rd-order magic torus displays just one magic square. Although there are two crossed magic diagonals on the torus, they only produce a single magic intersection over the number 5, whilst the second intersection occurs in the interval between the numbers 6, 4, 8 and 2. It is interesting to note that the mean number of 6+4+8+2 is 5, and that the mean numbers of the couples 6+4 and 8+2 are also 5.
order 3 magic torus schema of magic diagonals
We can deduce that basic (not pandiagonal, semi-pandiagonal or partially pandiagonal) odd number N-order tori  display not only 1 basic N-order magic square, but also N²-1 semi-magic N-order squares. For example, the smallest 1st-order magic torus displays 1 basic 1st-order magic square and 1²-1=0 semi-magic 1st-order squares. It is interesting to note that the first-order magic torus can be visualised either as a basic magic torus, or even as a pandiagonal torus!

1, (the number of third-order magic tori), is now the third number of the sequences A270876 "Number of magic tori of order n composed of the numbers from 1 to n^2" and A271104 "Number of magic and semi-magic tori of order n composed of the numbers from 1 to n^2," published by the On-Line Encyclopedia of Integer Sequences (OEIS).


New development!


Posted on the 21st January 2018, an article entitled "Multiplicative Magic Tori" shows that the 255 magic tori of order-4 are different multiplied states of 82 Multiplicative Magic Tori (MMT) of order-4!


Acknowledgements


I wish to express my gratitude to Walter Trump, not only for his valuable advice concerning the choice of terminology, but also for his computing skills that identified the magic torus type 4.04, and enabled a precise count.

I wish to thank Miguel Angel Amela who very kindly programmed a count of 4x4 broken diagonal solutions of the fourth-order magic squares, the results of which confirm the findings of the above study.

Since publishing this study I have become aware of Aale de Winkel's "Magic Encyclopedia" database Order 04 square group theory. I wish to belatedly acknowledge Aale de Winkel's work, which, although quite different to mine, (we neither use the same reasoning nor come to the same conclusion), is complementary. Please note that in his study Aale de Winkel uses analytic numbers ranging from 0 to 15 instead of the regular numbers 1 to 16. This does not change the magical properties of the squares but you need to add 1 to each number to see the traditional Frénicle versions.

I wish to thank Kanji Setsuda for pointing out the importance of associated or self-complementary magic squares. This has lead me to create a specific subdivision of the semi-pandiagonal tori.

My thanks also go to Dwane Campbell, who has published a very interesting comparative study of the Dudeney and Walkington Order-4 magic square classifications in the three pages that follow:
"Analysis of Order-4 Magic Squares,"
"Order-4 Magic Squares Grouped by Base Square Quartets,"
"Features in Order-4 Magic Squares."

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