Magic cube classes
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Every magic cube
Magic cube
In mathematics, a magic cube is the 3-dimensional equivalent of a magic square, that is, a number of integers arranged in a n x n x n pattern such that the sum of the numbers on each row, each column, each pillar and the four main space diagonals is equal to a single number, the so-called magic...

 may be assigned to one of six magic cube classes, based on the cube characteristics.

This new system is more precise in defining magic cubes. But possibly of more importance, it is consistent for all orders and all dimensions of magic hypercube
Magic hypercube
In mathematics, a magic hypercube is the k-dimensional generalization of magic squares, magic cubes and magic tesseracts; that is, a number of integers arranged in an n × n × n × .....

s.

Minimum requirements for a cube to be magic are: All rows, columns, pillars, and 4 triagonals must sum to the same value.

The six classes

  • Simple:

The minimum requirements for a magic cube are: All rows, columns, pillars, and 4 triagonals must sum to the same value. A Simple magic cube
Simple magic cube
A simple magic cube is the lowest of six basic classes of magic cube. These classes are based on extra features required.The simple magic cube requires only the basic features a cube requires to be magic. Namely; all lines parallel to the faces, and all 4 triagonals sum correctly. i.e...

 contains no magic squares or not enough to qualify for the next class.
The smallest normal simple magic cube is order 3. Minimum correct summations required = 3m2 + 4
  • Diagonal:

Each of the 3m planar arrays must be a simple magic square
Simple magic square
A simple magic square is the lowest of two basic classes of magic square. It has the minimum requirements for a square to be considered magic. All lines parallel to the edges, plus the two main diagonals must sum to the magic constant...

. The 6 oblique squares are also simple magic. The smallest normal diagonal magic cube is order 5.

These squares were referred to as ‘Perfect’ by Gardner and others! At the same time he referred to Langman’s 1962 pandiagonal cube also as ‘Perfect’.

Christian Boyer and Walter Trump now consider this and the next two classes to be Perfect. (See Alternate Perfect below).
A. H. Frost referred to all but the simple class as Nasik cubes.
The smallest normal diagonal magic cube is order 5. See Diagonal magic cube
Diagonal magic cube
A Diagonal Magic Cube is an improvement over the simple magic cube. It is the second of six magic cube classes when ranked by the number of lines summing correctly....

. Minimum correct summations required = 3m2 + 6m + 4
  • Pantriagonal:

All 4m2 pantriagonals must sum correctly (that is 4 one-segment, 12(m-1) two-segment, and 4(m-2)(m-1) three-segment). There may be some simple AND/OR pandiagonal magic squares, but not enough to satisfy any other classification.
The smallest normal pantriagonal magic cube is order 4. See Pantriagonal magic cube
Pantriagonal magic cube
A pantriagonal magic cube is a magic cube where all 4m2 pantriagonals sum correctly. There are 4 one-segment, 12 two-segment, and 4 three-segment pantriagonals...

.
Minimum correct summations required = 7m2. All pan-r-agonals sum correctly for r = 1 and 3.
  • PantriagDiag:

A cube of this class was first constructed in late 2004 by Mitsutoshi Nakamura. This cube is a combination Pantriagonal magic cube
Pantriagonal magic cube
A pantriagonal magic cube is a magic cube where all 4m2 pantriagonals sum correctly. There are 4 one-segment, 12 two-segment, and 4 three-segment pantriagonals...

 and Diagonal magic cube
Diagonal magic cube
A Diagonal Magic Cube is an improvement over the simple magic cube. It is the second of six magic cube classes when ranked by the number of lines summing correctly....

. Therefore, all main and broken triagonals sum correctly, and it contains 3m planar simple magic squares. In addition, all 6 oblique squares are pandiagonal magic squares. The only such cube constructed so far is order 8. It is not known what other orders are possible. See Pantriagdiag magic cube
Pantriagdiag magic cube
A Pantriagonal Diagonal magic cube is a magic cube that is a combination Pantriagonal magic cube and Diagonal magic cube. All main and broken triagonals must sum correctly, In addition, it will contain 3m order m simple magic squares in the orthogonal planes, and 6 order m pandiagonal magic squares...

. Minimum correct summations required = 7m2 + 6m
  • Pandiagonal:

ALL 3m planar arrays must be pandiagonal magic squares. The 6 oblique squares are always magic (usually simple magic). Several of them MAY be pandiagonal magic.
Gardner also called this (Langman’s pandiagonal) a ‘perfect’ cube, presumably not realizing it was a higher class then Myer’s cube. See previous note re Boyer and Trump.
The smallest normal pandiagonal magic cube is order 7. See Pandiagonal magic cube
Pandiagonal magic cube
In a Pandiagonal magic cube, all 3m planar arrays must be panmagic squares. The 6 oblique squares are always magic. Several of them may be panmagic squares....

.
Minimum correct summations required = 9m2 + 4. All pan-r-agonals sum correctly for r = 1 and 2.
  • Perfect:

ALL 3m planar arrays must be pandiagonal magic squares. In addition, ALL pantriagonals must sum correctly. These two conditions combine to provide a total of 9m pandiagonal magic squares.
The smallest normal perfect magic cube is order 8. See Perfect magic cube
Perfect magic cube
In mathematics, a perfect magic cube is a magic cube in which not only the columns, rows, pillars and main space diagonals, but also the cross section diagonals sum up to the cube's magic constant....

.

Nasik;
A. H. Frost (1866) referred to all but the simple magic cube as Nasik!

C. Planck (1905) redefined Nasik to mean magic hypercubes of any order or dimension in which all possible lines summed correctly.
i.e. Nasik is a preferred alternate, and less ambiguous term for the perfect class.
Minimum correct summations required = 13m2. All pan-r-agonals sum correctly for r = 1, 2 and 3.

Alternate Perfect
Note that the above is a relatively new definition of perfect. Until about 1995 there was much confusion about what constituted a perfect magic cube (see the discussion under diagonal:)
. Included below are references and links to discussions of the old definition

With the popularity of personal computers it became easier to examine the finer details of magic cubes. Also more and more work was being done with higher dimension magic Hypercubes. For example, John Hendricks constructed the world's first Nasik magic tesseract in 2000. Classed as a perfect magic tesseract by Hendricks definition.

Generalized for All Dimensions

A magic hypercube of dimension n is perfect if all pan-n-agonals sum correctly. Then all lower dimension hypercubes contained in it are also perfect.

For dimension 2, The Pandiagonal Magic Square has been called perfect for many years. This is consistent with the perfect (nasik) definitions given above for the cube. In this dimension, there is no ambiguity because there are only two classes of magic square, simple and perfect.

In the case of 4 dimensions, the magic tesseract, Mitsutoshi Nakamura has determined that there are 18 classes. He has determined their characteristics and constructed examples of each.
And in this dimension also, the Perfect (nasik) magic tesseract has all possible lines summing correctly and all cubes and squares contained in it are also nasik magic.

Another definition and a table

Proper:
A Proper magic cube is a magic cube belonging to one of the six classes of magic cube, but containing exactly the minimum requirements for that class of cube. i.e. a proper simple or pantriagonal magic cube would contain no magic squares, a proper diagonal magic cube would contain exactly 3m + 6 simple magic squares, etc. This term was coined by Mitsutoshi Nakamura in April, 2004.



Notes for table
  1. For the diagonal or pandiagonal classes, one or possibly 2 of the 6 oblique magic squares may be pandiagonal magic. All but 6 of the oblique squares are ‘broken’. This is analogous to the broken diagonals in a pandiagonal magic square. i.e. Broken diagonals are 1-D in a 2_D square; broken oblique squares are 2-D in a 3-D cube.
  2. The table shows the minimum lines or squares required for each class (i.e. Proper). Usually there are more, but not enough of one type to qualify for the next class.

See also

  • Magic hypercube
    Magic hypercube
    In mathematics, a magic hypercube is the k-dimensional generalization of magic squares, magic cubes and magic tesseracts; that is, a number of integers arranged in an n × n × n × .....

  • Nasik magic hypercube
  • Panmagic square
    Panmagic square
    A pandiagonal magic square or panmagic square is a magic square with the additional property that the broken diagonals, i.e...

  • Space diagonal
    Space diagonal
    In a rectangular box or a magic cube, the four space diagonals are the lines that go from a corner of the box or cube, through the center of the box or cube, to the opposite corner...

  • John R. Hendricks

Further reading

  • Frost, Dr. A. H., On the General Properties of Nasik Cubes, QJM 15, 1878, pp 93–123
  • Planck, C., The Theory of Paths Nasik, Printed for private circulation, A.J. Lawrence, Printer, Rugby,(England), 1905
  • Heinz, H.D. and Hendricks, J. R., Magic Square Lexicon: Illustrated. Self-published, 2000, 0-9687985-0-0.
  • Hendricks, John R., The Pan-4-agonal Magic Tesseract, The American Mathematical Monthly, Vol. 75, No. 4, April 1968, p. 384.
  • Hendricks, John R., The Pan-3-agonal Magic Cube, Journal of Recreational Mathematics, 5:1, 1972, pp51–52
  • Hendricks, John R., The Pan-3-agonal Magic Cube of Order-5, JRM, 5:3, 1972, pp 205–206
  • Hendricks, John R., Magic Squares to Tesseracts by Computer, Self-published 1999. 0-9684700-0-9
  • Hendricks, John R., Perfect n-Dimensional Magic Hypercubes of Order 2n, Self-published 1999. 0-9684700-4-1
  • Clifford A. Pickover
    Clifford A. Pickover
    Clifford A. Pickover is an American author, editor, and columnist in the fields of science, mathematics, and science fiction, and is employed at the IBM Thomas J. Watson Research Center in Yorktown, New York.- Biography :He received his Ph.D...

    (2002). The Zen of Magic Squares, Circles and Stars. Princeton Univ. Press, 2002, 0-691-07041-5. pp 101–121

External links

Cube classes
Perfect Cube
Tesseract Classes
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