The Cast Nutcase created by the Dutch inventor of the puzzle, Oskar, has two objectives: Remove the small nut by dismantling the cast iron box. Lovers of molded puzzles (nutcases) can have fun trying to change the formulation of the \”nut-case\” bolt at \”Nut box\”. Difficulty : Grand Master Please note, the puzzles are provided without resolution instructions. However, many videos can be found on the internet and YouTube explaining how to resolve them.