Details: Have you conquered the One Tough Puzzle challenge? Up for something even more puzzling? With only 16 pieces, this puzzle may look easy...but just when you think you've solved it, the last piece proves you wrong. Assemble the puzzle in a pyramid shape, 6 interlocks should extend outside of the border, & the other 6 interlocks should be inverted. 600, 000 wrong ways to assemble, one solution! Ideal for: A great game for children aged 10 years & above.