Each player plays one piece per turn, the first player to align 4 pieces in any direction wins the game.
Popout: at your turn, you have the possibility to not add a token but to remove one of yours at the bottom of a column. All the upper tokens will then fall down one row.
5 in a row: same rules apply, but you need to align 5 instead of 4 pieces. The initial board is not empty, both left and right columns are filled with alternated colors.
Torus: in this game, the board is curved like a cylinder so that left and right cells become adjacent