The Japanese company Hanayama have been making a range of cast metal puzzles for over a quarter of a century now. The design of their puzzles is amazing, as is the craftmanship with which they are made.
CAKE is Level 4 Difficulty (i.e. fairly difficult!) It comes in a smart presentation box. A quarter of this cake has been cut away, showing three identical layers inside. This puzzle looks simple but it is very ingenious. The challenge is firstly to disassemble the parts, then reassemble the puzzle to the starting position, ready for the next victim!
These puzzles do not come with a solution. However if you visit the distributor website at http://www.eureka-puzzle.eu/eureka/index.php?/all-cast-puzzle-solutions.html and enter the complete barcode found on the box your puzzle came in, you will be able to access the solution.