All numbers are in a slide.Slides from left to right. Under number 4 is the free hole. A difficult puzzle, but it can be solved. Assignments on the back of the puzzle.Material acrylic.
Old puzzle. Copy produced by puzzle design Ton Delsing.9 cardboard pieces. The puzzle was patented in 1911, This variation on Thurston's puzzle was used as an advertisement for soap. The idea was to arrange the cards so that each center circle contained four different colors and each half circle contained two.