Gamehelpquatrix

Line up 4 pieces of your color in any direction or capture 4 squares of the same color.

If you play an X, your opponent must play a piece of their choice in one of the diagonal directions from played cell.

If you play a □, your opponent must play a piece of their choice in one of the orthogonal directions from the played cell.

If there are no more valid spaces, you may play anywhere you like.