Levitating Objects on an Air Table —

Air-tables create a thin film of air capable of supporting objects and causing them to levitate. By adding grooves to the table or the object, Professor John Hinch at the University of Cambridge was able to control the objects motion and describe the resultant acceleration in terms of a simple scaling relationship involving gravity and the aspect ratio.

https://www.youtube.com/watch?v=9yeAcz45Qm8