Put the same colours together. The white center piece can only slide up and down.Pieces cannot fall out due to transparent top plate. Matererial. Acryl.The pieces are covered with transparent foil. You can slide without damage.
Copy produced by puzzle design Ton Delsing. Old Puzzle. The following text is printed on the back of the box.With the 9 pieces a large square or other figuresis to be formed in such a way that the same colour shal not occur more then once in any row horizontal or vertical (in the square also diagonal) This must be done for each symbol..Material . Cardboard pieces