Cat swing toy

Cat swing toy. Self balancing.

Requires:
2pcs 6900 ball bearings (only needed for full functionality. can be replaced with fixed adapter)
1pc 2mm diameter rod (best is carbon/glass fiber. Steel rods, eg bike wheel spokes also works). can be replaced with anything really.

Sand or anything heavy to counterweight the ball and making it go back up.

Print the ball light, it is easily replaceable, even with a ping pong ball.
Print the 2 shafts with 50% infill. you might have to play with size, sanding or gluing them into place. They are small and fast to reprint.