Professor Puzzle Six Wooden Puzzles in Wooden Chest _ Bonus Twisted Nails &ldquo;Separate the Nails&rdquo; Puzzle Series of 6 wood puzzles in six levels of ascending difficulty from Professor Puzzle. Puzzles measure approximately 2 x 2 x 2 inches. Object is to separate all the puzzle's pieces and then rebuild. Wood chest with separate compartments for each puzzle. Sliding plexiglass top. Bonus: Twisted NAILS - "Separate the Nails" puzzle. A slightly tricky but fun puzzle.