Trilite for Mac

From John Mauro Software:

Trilite is a shareware game similar to tic-tac-toe, but much more fun and challenging. The object is to get three adjacent squares set to your color. These squares may be horizontal, vertical, or diagonal. On your turn, click on any empty square to fill it with your color. Sound simple enough? Well, here's the trick: you may only have three squares occupied at a time. Once you click on a fourth square, the first one you selected becomes empty again, allowing your opponent to make a surprise move. You may play against another person or a computer player (with two levels of difficulty).