Ricardo Garza Marcos' 'Pong Chair' is proof that hacking the legs off a chair doesn't mean it becomes useless. Legless stools are still stools.
The Pong Chair is a clever design. The chair is hollowed out and has a lead balancing weight on the bottom so that it'll wobble but won't fall down. Imagine the surprise and shock of people when your perch yourself on this precarious seat and it stays upright! The Pong Chair brings the shock value, people.