This week's selection is the Alien Ball Bearing by Thingiverse creator Steve Medwin.
This bizarre shape actually functions, slightly. Medwin says:
This thing has five independent balls that roll around inside the organic ring. It reminds me of an alien version of a ball bearing, even though the inside doesn't roll separately from the outside like a real bearing does. It's another fun desk toy to play with during a slow meeting or conference call. If you aim compressed air at the balls at just the right angle, you can get them spinning pretty quickly around the ring!
One side of the ring is flat, enabling you to display the object on edge as it sits on your desk.
This design is available for free download at Thingiverse. However, be warned that printing this will be challenging. The balls are "loose" and therefore you must print this object with supports. We recommend using a dissolvable support material such as PVA for this, as you'll want to have the smoothest finish on the balls. Alternatively, you could print this item with a powder-based 3D printer at a 3D print service like Shapeways, Sculpteo or i.Materialise.