Er, instructions are available in-game (select Quarto Help from the Help menu, or hit command-?). They are also on the webpage (included here for the lazy): Objective: The object of the game is to place four pieces in a row (horizontal, vertical, or diagonal) that share some common trait (tall/short, dark/light, round/square, or hollow/solid). When you place the last piece in the row, call Quarto (by hitting the button) and you win. How to play: Game play is simple. One play chooses a piece for his opponent to use and gives it to them. The other player then places the piece on the board and presents the first player with the next piece for them to use.