Tetris fans had a little fun with a skyscraper-sized version of the classic video game.
The Philadelphia event created a spectacle against the night sky that organisers hoped would inspire onlookers and players to think about the possibilities of technology.
The 29-storey Cira Centre, which has hundreds of LED lights embedded in its glass facade, normally displays colourful geometric patterns at night.
Yesterday, images of supersized shapes "fell" on two sides of the mirrored tower as competitors used joysticks to manoeuvre them into place.
Tetris, created by Russian computer programmer Alexey Pajitnov in 1984, challenges players to rotate and arrange falling shapes into complete rows.
Yesterday's event kicked off a citywide series of events called Philly Tech Week.
It also celebrated the upcoming 30th anniversary of Tetris, a game revered as the epitome of elegance and simplicity, said Frank Lee, a digital media professor at Drexel University.
He already holds the Guinness World Record for the world's largest architectural video game display for playing Pong on one side of the Cira Centre last year. Pong is an electronic version of paddleball developed by Atari in 1972.
Tetris became a global phenomenon in the late 1980s after game designer Henk Rogers, who had seen it at a trade show in Las Vegas, acquired the rights and struck a deal to put it on Nintendo's original Game Boy.
Mr Rogers said he cannot believe the longevity of Tetris, which decades later continues to mesmerise players on more than 30 platforms.
"If a game lasts a year, that's amazing," said Mr Rogers, now managing director of The Tetris Company. "They usually go out of style very quickly."
He said several new Tetris products and initiatives are planned for release around its June 6 anniversary.