The "nuts and bolts" appearance may lull you into believing this to be a straightforward puzzle, but it is a total brain drain. Inventor Oskar van Deventer presents two challenges: 1) remove the small nuts by disassembling the nutcase, and 2) change the order of the wording on the bolts from "nut-case" to "case-nut." Each of these beautiful dexterity puzzles is made of intricately molded zinc alloy and features bright, brushed, or antiqued finishes. They make classy, eye-catching, desktop accessories as well as challenging diversions. Levels of difficulty are clearly marked: Level 1 - Easy, Level 2 - Fairly Easy, Level 3 - Moderate, Level 4 - Challenging, Level 5 - Difficult, and Level 6 - Very Difficult. The included booklet illustrates the challenge for each puzzle in the series, but please note that solutions are not provided in order for you to experience the "fun" and "agony" of solving these puzzles.