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.
Try to open the puzzle by removing the 4 cylinders with the numbers. (2014 is year of design). Inlaid numbers. Materal acrylic.If you have problems to open it, use the green tool.But try to find out why this tool is in the BOX!!!GOOD LUCK!