A Philadelphia skyscraper became a giant Tetris video game Saturday night.
Hundreds of fans watched as competitors used joysticks to maneuver the Tetris shapes as they 'fell' down the sides of the 29-story building (the Cira Centre).
The building has LED lights embedded in its glass facade. Last year the lights were used to play the video game Pong.
The Tetris game kicked off a citywide series of events called Philly Tech Week. It also celebrated the upcoming 30th anniversary of Tetris.