The mathematics problem is a bit like Sudoku on steroids. It’s called Euler’s officer problem, after Leonhard Euler, the mathematician who first proposed it in 1779. Here’s the puzzle: You’re commanding an army with six regiments. Each regiment contains six different officers of six different ranks. Can you arrange them in a 6-by-6 square without repeating a rank or regiment in any given row or column? More here.
Excellent article, interesting problem, fascinating solution.