I designed this with the plan of placing a 3/8" ball bearing in its center. This should be easy in a flexible material; it wasn't so easy in steel. But now that I see it, I'm not sure the center isn't better left open...your call to make.
I'm a designer for 3D printing, here are some sculptures and math models. In sizes from jewelry to handheld sculpture, they're a mix of geometry, computation and hand drawing.
Some are exclusive to Shapeways, others are also on my main site at http://bathsheba.com.
Thanks for visiting! These are my happy places, I hope you like them too.