Experiment in trying to make a fidget spinner without bearings. Printed in 100% infill with a couple drops of oil* in the pivot joints, it should spin for 15-20 seconds fairly easily, but I haven't gotten it to go over 30 seconds. It might do better with a heavier filament.
It turns out it can be disassembled fairly easily, so there wasn't really a good reason to design it to be printed as a single piece. Taking it apart is the easiest way to oil the pivots points.
I used the 0.05mm gap version but I also included a couple other gap distances. The pivot should be stuck slightly when it comes off the printer, but it should separate easily when spun. If you notice any wobbling, it's too loose and you may need to use a smaller gap or overextrude a bit.
Atomic Filament Dark Cherry Red PLA, Translucent Orange PLA, and Fillamentum Blue PLA*