Nim

Nim is a simple game used for examples in combinatorial game theory. The rules of nim are simple:

1. The game begins with some piles of counters.
2. Players alternate turns.
3. On a turn, a player takes counters from a pile. At least one counter must be taken, but up to 3. All counters must be in the same pile.
4. If a player cannot take a counter, that player loses.

There is a simple mathematical strategy to play the game perfectly. If both players play perfectly, the winner is determined by the initial setup.