What could be the biggest game of "Pong" is underway in Philadelphia.
The classic Atari video game is being played on the facade of a mirrored, 29-story skyscraper.
Hundreds of built-in LED lights embedded in the north face of the Cira Centre are replicating the familiar paddles and ball with gamers controlling giant, table-mounted joysticks across the Schuylkill River from the building.
It's being played Friday and Wednesday to bookend Philly Tech Week, an annual series of events, seminars and workshops spotlighting the city's technology and innovation communities.
Explore further: Philadelphia gets ready to play 'Pong' on building (Update)