You must have a browser with Active-X controls enabled and supports Java to play Concentrate! A tile is flipped by clicking on its blue tile back. Begin play by flipping two tiles, one at a time. If the tiles match, they will be removed. If they do not match, they will be flipped back. Repeat this process until all twelve pairs of matching tiles have been removed. If you are successful, you can add your name to our score list!
Earth's magnetic poles reverse their geographic locations every 300,000 years. The last event happened 780,000 years ago.