The rules of the tic tac toe game are the following:
- a game is over when all fields are taken
- a game is over when all fields in a column are taken by a player
- a game is over when all fields in a row are taken by a player
- a game is over when all fields in a diagonal are taken by a player
- a player can take a field if not already taken
- players take turns taking fields until the game is over
- there are two player in the game (X and O)