Welcome to the game of Nim. Initially a random number of coins are arranged in stacks; you control their number and maximum capacity. The rules are simple: you start first. You and the computer alternate in removing any number of coins from any single stack. Whoever takes the last coin wins. You click on a coin to remove it and all the ones above it. The computer then signals its turn. Click again to allow it to play and so on until one of you wins.