Previously I wrote about latin squares and set a puzzle. We can demonstrate this for an n x n latin square where n = 12 In the above images, the normalised latin square only has 12 different pairs out of a possible 66. The density plot shows the pairings in the lower triangle, grey represents 0. A randomly generated latin square (where all rows and all columns feature 1 to 12 exactly once) is shown where all possible pairs are captured.