I set out to make a puzzle box that is nearly impossible to open and it would seem I succeeded. Two rotating blocks that hide a maze inside must be navigated all the way up, down, then back up again. So far, once closed, no one has been able to open it (without cheating). Not even myself, which proved to be rather inconvenient.
Two tips for anyone looking to print and use this:
1) Don't print the blocks with supports, they are impossible to clean up and don't need them
2) Don't put anything too important in it. I still can't open it without looking back to the model.