Holographic Interface - round interface - Ringo from Ivan Tihienko on Vimeo.
Circular user interfaces are very futuristic. I think real interfaces are often square because it's more space efficient than circular shapes, and space is always at a premium. But when you project on the ground, you have lots of space. Pico projectors are just around the corner so it's time to start thinking about what's different about a projected interface.