DONUTS Hanayama Cast Metal Brainteaser Puzzle - Level 4 DONUTS is the 2011 New Metal Disentanglement Style Puzzle from Hanayama Puzzles of Japan. Level 4 difficulty (on a scale of 1 to 6 .... as rated by the manufacturer). Your experience may differ. Object is to separate the pieces with clever movements. No FORCE ever. Second Puzzle is to put back together. Great for ages 12 to 105 years. Some very bright 10-11 year olds may also enjoy.