This is a unique string puzzle. The objective is to get all the "circuit breakers" to fit in the holes. There is only one pattern in which they can all be fitted. Everything is attached by strings to the central core, so there are no loose pieces.
Wooden Plug String 3D Puzzle Brain Teaser Game
Unique String Puzzle
Wood construction with strings
1 pattern solution
Everything is attached by strings to the central core - no loose pieces