The following was suggested by a link within this evening's earlier Kane site link.
Peter J. Cameron's weblog on August 26, 2010—
A Latin square of order n is a n × n array with entries from the symbol set {1, 2, …, n }, such that each symbol occurs once in each row and once in each column. Now it is not hard to show that, up to permutations of the rows, columns and symbols, there are only two Latin squares of order 4:
| 1 |
2 |
3 |
4 |
| 2 |
1 |
4 |
3 |
| 3 |
4 |
1 |
2 |
| 4 |
3 |
2 |
1 |
|
| 1 |
2 |
3 |
4 |
| 2 |
3 |
4 |
1 |
| 3 |
4 |
1 |
2 |
| 4 |
1 |
2 |
3 |
|
Some related literary remarks—
Proginoskes and Latin Squares.
See also "It was a perfectly ordinary night at Christ's high table…."