This is a simple yet challenging box puzzle which I designed. The idea is to stack the pieces in the correct permutation to fill the box. It's a perfect icebreaker or gift for a friend, but make sure you know how to solve it!
If you're stuck, I've included images of the puzzle in it's solved state and inside the box, so feel free to use those images as a reference.
Everything is 3d printable, you can do it all in one sitting. Two of the pieces will need support (although I did my best to minimise this).