SMOOTH OPERATOR _ Tavern Puzzles Heavy Metal Disentanglement-Style Brain Teaser_ BONUS Twisted Nails Puzzle Old fashioned heavy metal brain teaser disentanglement puzzles. Bonus: Twisted Nails Separate the Nails Puzzle. Objective of Smooth Operator is to remove the large 2.5" diameter ring (indicated by blue arrows) which is found hanging towards the bottom of the puzzle. Replacing the ring to the starting position is equally as challenging. Rated as a level 2 "Intermediate / Challenging" (on a scale of 1 to 4). On this scale both level 3 and 4 are very challenging. Packaged in sturdy white box, cloth bag and with solution.