The Hanayama Spiral puzzle is unique in its simplicity. It is made of 5 jigsaw-type pieces connected to each other in cyclic fashion. The pieces can slide against each other up and down, but seemingly can never get separated. Even though initially the task looks impossible, playing for a bit with the puzzle will probably give you an idea how to solve it. What is nice about the solution is how simple it looks, just like the design itself. Putting back together Spiral is a bit more complicated and requires good amount of trial and error. Overall, this is a very good puzzle and a highly recommended toy.