A chessboard with two opposite corners cut away, after the old puzzle. Both missing corners are dark, so thirty-two light squares remain against thirty dark, and every domino covers one of each. The dominoes try anyway: thirty of them fill the board, two light squares are left apart on the bottom row, and a last domino tries both ways and is blocked each time. The board clears. Then the dark corner builds itself back and a light square is cut instead. Thirty-one and thirty-one: the balance dial drops from two to zero. A single loop runs through all sixty-four squares, the dominoes stand up along it, a gold fuse is lit, and they fall one by one, each landing on exactly its two squares. Thirty-one of thirty-one. It was never about the corners, only the colours.