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.
During an International Puzzle Party (IPP) I received a drawing with 2 puzzlesfrom Serhiy Grabarchuk. I made it. Assignment on the back of the box see photo 3.Material 9 cardboard pieces.