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!
The alignment of Sun, Venus, and Earth comes in pairs that are eight years apart but separated by over a century. For example, the last pair happened in December 1874 and December 1882. The next pair would be in June 2004 and June 2012. After 2012, subsequent pairs will be in December 2117 and December 2125.