Two Bolts Puzzle
This is a short spatial awareness puzzle. You hold two bolts as shown below with their threads interlocked. You then move the two bolts around each other with the same movement as if you are twiddling your thumbs. We’ll say that someone standing to your right-hand side would see them going clockwise. However you hold the individual bolts tightly so they don't rotate through space, i.e. if you were to paint a line along the top of each bolt then that line would continue to face the ceiling throughout the process.
The question is: do your hands get closer together, further apart, or stay the same distance from each other?
I'm hoping this is counterintuitive to you as it was to me. The bolts’ movements cancel each other out, with one threading in and one threading out and so you can do it forever with your hands getting no closer together.