On your turn you choose a piece for your opponent.
Your opponent then places that piece on any empty cell.
Then your opponent chooses a piece for you, and so on.
Winning
Get four pieces in a line (row, column, or diagonal) that all share at least one common attribute.
For example: all four are tall, or all four are round, or all four are dark, etc.
The player who places the fourth piece wins automatically.
Reviewing moves
Select a move in the history or use the arrow controls. Choose Go to end to return to your game. Resuming an earlier position discards the later moves.
Draw
If all 16 pieces are placed without anyone winning, the game is a draw.