Inspired by the Möbius Strip concept, this is a small bracelet like piece that has a small .25in dia ball that rols all around the "path" made by the the Mobius design. The inside diameter is about 2.5 inches. Don't forget it would need to fit over your hand, not just your wrist, when measuring.
This has been sucessfully printed. You can view a short video of a small test print I did to display the cross section here: http://www.youtube.com/watch?v=pVSuuBWJ7E4