KEY II Hanayama Cast Metal Brain Teaser Puzzle (Level 2) Hanayama's Key II Puzzle is a high quality cast metal brain teaser from inventors Otake & Wong Discover how to separate these two interlocking pieces and then try to reassemble them! Hanayama cast metal brain teasers have 6 levels of difficulty and each puzzle is Mensa-rated Level 2 puzzles are considered fairly easy by most puzzlers