To play a game of "Tetris" is to invite a geometric invasion into your mind. After hours of intense block manipulation, you finally set aside your gaming device. You take a deep breath, close your eyes -- and there the frenzied, multicolored tetrominoes continue to cascade across your vision. They build walls in your dreams and shape the patterns of your very thought. What's going on inside the mind of a "Tetris" player and what can we learn from so-called "Tetris" syndrome. In this episode of Stuff to Blow Your Mind, Robert and Joe explore.