QUARTET Hanayama Cast Metal Brain Teaser Puzzle OBJECT: Completely separate the four square-shaped metal pieces. Level 6 Difficulty (where level 1 is easier and level 6 most difficult). Your experience could differ. Small, compact, beatifully designed brain teaser puzzle. Guaranteed to sharpen your skills at taking things apart and putting them back together. Recommended for ages 12 through adult. (Some very bright 8 to 11 year olds may also enjoy.)