Eights rooks are placed randomly on a chess board. What is the probability that none of the rooks can capture any of the other rooks? Translation for those who are not familiar with chess: pick 8 unit squares at random from an 8 × 8 square grid. What is the probability that no two chosen squares share a row or a column? Hint. You can think of placing the rooks both with or without order, both ap- proaches work.