Tetris effect

Tetris effect is where a person devoting a large amount of time to a particular pattern-based activity (which in this case is Tetris) will start unconsciously thinking and dreaming about it. People who played Tetris for a prolonged amount of time could find themselves thinking about ways different shapes in the real world can fit together, such as the boxes on a supermarket shelf, the buildings on a street, or hallucinating pieces being generated and falling into place on an invisible layout.