A print-in-place rolling element bearing. I've got some plans for incorporating this concept into a bigger project, but I think bearing came out as a fun little desk toy/fidget toy in its own right! (at least to me :) )
Print should not require any supports, brims, etc. I printed the one pictured coarsely with a 0.6 nozzle @ 0.48 layers in PETG.
I think I was a bit too conservative on the clearances for the rolling elements, but she holds together and rolls pretty well! I've got some ideas for things I want to experiment with to get a preload into the bearing. So hopefully there will be some fun follow-ups coming soon