It's a three-piece coordinate-motion puzzle. To
assemble it you have to put together the three parts moving them simultaneously towards
the center of the puzzle.
It looks simple and elegant, and it can be made out
of flat pieces of wood or plywood using an ordinary scroll saw without tilting.
Proportions can vary:
The Clips has a hollow cubical cavity inside of it,
so to some extent it's a Box Puzzle.
The space contains a little secret which makes
assembling more challenging.