Schloß Dick (Voidlock) - Wooden Lock Puzzle Brain Teaser

I bought this for my 19 yr old grandson who just started college as an Aerospace Engineer at Cal State Poly. I was trying to get him on of the most difficult puzzles I could find. After looking at it for a few minutes, he sat there in front of me on Christmas eve and figured out the puzzle in 30 minutes then put it back together again. I was shocked. The next day he completed this lock in less than 10 minutes while I watched. If your looking for a difficult puzzle, try a different one.