Effect: There are four islands in an ocean. Each has a king, queen, a son named Jack (the Jack will be used,) and a dog named Ace (the Ace will be used.) One day, a hurricane storms through the ocean, creating complete chaos and wiping everything on ... Read more of Four Islands at Card Trick.ca
It will be seen that every square of the board is either occupied or
attacked. The puzzle is to substitute a bishop for the rook on the same
square, and then place the four queens on other squares so that every
square shall again be either occupied or attacked.