What is a puzzle box?
A puzzle box (also called secret or trick box) is a box that need several steps to be opend. Some has keys, some doesn't. Japanese puzzle boxes does not, they have sliding systems. You can search it on YouTube or Google or someting.
Lego puzzle boxes, has often keys (from what I've seen or build), but you can also build sliding systems. They can be big, or small, or green... However, it's the puzzle that counts.
Of course you can destroy a lego puzzle box with a hammer, but why? Funnier to open it the real way.