There are two goals to the Cast Nutcase created by the Dutch puzzle inventor, Oskar:
1. Remove the small nut by disassembling the cast nutcase.
2. Cast puzzle enthusiasts (nutcases) can enjoy trying to change the wording on the bolt from 'nut-case' to 'case-nut'.
The key word is "Interlocking."
Level 6 of 6 (extremely difficult)