Quarto is an abstract board game for 2 players. Players compete to place pieces on a 4x4 grid, to be the first player to make a line of four pieces (or in advanced variant, also a 2x2 square) where all of them share some characteristic. The twist is that the opponent chooses the piece to be played.

Start of the game

The board is divided into 16 spaces in a 4x4 grid. There are 16 pieces. Each piece can be light or dark, tall or short, circular or square, and solid or hollow. Each possible combination (for example, light/tall/circular/solid or dark/short/square/hollow) appears exactly once. The board starts off empty; all pieces are off the board.

Player's turn

In a player's turn, two steps happen. First, the opponent chooses a piece, then the player chooses a space to place the piece. Any piece still off the board may be selected, and any empty space may be selected.

End of the game

The game ends when there is a line of four occupied spaces, of which all four pieces in the line share a common trait (for example, all light or all short). The player that places the last piece that forms that line of four (not the opponent who selected it) is the winner.

In the advanced variant, a 2x2 area that share a common trait also ends the game, winning for the player that places the piece.