Steel, ball bearings, 3” diameter
Here are four printed metal parts (not six!) and nine tungsten carbide bearings holding them together/apart. There could be 12 bearings, but there aren't. It is a pure snap-fit, without adhesive or other cheating. I wouldn't class it as a puzzle, though, because it's the devil to assemble.
I produced this for a year or two, and then it mysteriously stopped working: woouldn't assemble no more. I still have my magic pair of pliers that were the onlypliers which could put it together, but no dice.
What happened? Why did it ever work? Did I dream it?
If you have one, it might be a collector's item.