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.
12 pieces with inlaid letters. Pieces with tongue and groove. All pieces 20x20 mmSlide from the starting position ALBWHITE CK!!ET TO !WHITE !BLACK! On the back there is a slide up and down. This slide changes the free hole.Then slide to BLACK! WHITE! easy?Material Acrylic.