A group of scientists at Canada's Alberta University were the brains behind Chinook — a computer program designed to beat human competitors at checkers. In 1992, Chinook played world champion Marion Tinsley, who had remained nearly undefeated for more than four decades. Tinsley pulled out a victory that time around, and during a 1994 rematch, the human was forced to withdraw from the match for what would turn out to be cancer. Yet Chinook would become so good at checkers, so powerful at beating human competitors, that the program was eventually retired from play.