|5||5||I'm sure you know the Minesweeper game: you start out with a rectangle of water, divided into squares. Each of the squares may or may not contain a mine; you find out by clicking on it. If it held a mine, you die. If it didn't, it shows the total number of mines present in the eight surrounding squares. This hopefully gives you enough information to figure out that some neighbouring square is also "safe," and so on. Sometimes the game helps you a bit by revealing the squares that are absolutely obvious automatically.