Let me start with a formulation of the problem for people who aren't familiar with Magic: the Gathering. You have a stack of distinct cards face-down. You can apply the following action arbitrarily many times: Look at the top two cards of the stack. Return them to the stack both cards on top o...

Consider a chessboard with dimensions 10x10. You need to place the maximum number of queens on the board without any of them attacking each other. However, there’s an additional constraint: no queen can be in the same row, column, or diagonal as any other queen, and you must also place exactly on...

You stumble upon this puzzle in the newspaper, composed of only lines and numbers. 13—17 13—84 13—113 17—117 34—53 53—115 82—84 113—17 117—113 Unfortunately, you're a bit stuck. You call upon your friend Sherlock for a hint (he's very good at puzzles). After looking at it for a minute, he finally...