Suirodoku: what happens when you combine Sudoku with Euler's 1782 Graeco-Latin squares

Feb 13 · 2 min read · In 1782, Leonhard Euler imagined arranging 36 officers in a square so that no regiment and no rank repeated in any row or column. He couldn't solve it. The structure he imagined, Graeco-Latin squares, became a cornerstone of combinatorics. I turned i...