It contains 10 pieces with different placed holes upon them within a box. Try to find out the only combination to place the 10 pieces in the box, in two levels so that the holes of the upper level will match the holes of the second level.
With 10 wooden handmade pieces and a wooden case. Size 13cm x 13cm x 3cm height.
DIFFICULTY OF SOLUTION: ****
DIFFICULTY OF MEMORIZING: *****