The center piece can only slide up and down. Pieces cannot fall out through the transparent top plate. More assignments on the back of the puzzle. Material MDF.
The nummers are covered with transparent foil. You can slide without damage.
All numbers are in a slide.Slides from left to right. Under number 4 is the free hole. A difficult puzzle, but it can be solved. Assignments on the back of the puzzle.Material acrylic.
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.
The most difficult puzzle I have designed. The puzzle consists of 15 pieces. Some pieces can be slid under the edge. Goal: Make the numbers 1 to 9 from left to right in the frame There are different possibilities. But there is only one possibility to slide to a magic square. The numbers are engraved in the pieces. Matrial Acrylic.If you carefully open the puzzle (press the bottom of the title square piece) you will see a 4. Remember that.