Burr Puzzles are traditionally made of wood, but I made one that can be printed by a Cupcake. There are six pieces altogether with about a little more than a dollars worth of material. The puzzle is design for a perfect fit. If you want to make it more loose then you can modify the stl files for each piece. This particular puzzle takes fifteen steps to put together so it is quite fun. However, trying to figure out how take it apart is as much fun.To put the puzzle together refer to this web page: http://research.ibm.com/BurrPuzzles/Samples.html-Philippe Dubois' Burr 6.4 difficulty level