12 pieces with inlaid letters. Pieces with tongue and groove.Slide 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.
This puzzle is a copy produced by puzzle design Ton Delsing. Slid the numbers into order. Start: remove orange center piece & piece number ten. Green pieces are immovable.Material MDF.