Hi,
A few months ago I built a 3D Puzzle on a bored day. It just came into my mind and I built it. A lot of people tried it and most of them really liked it, because it wasn't impossible difficult, but certainly not easy.
A few days ago, I came across the puzzle again, and I decided to make building instructions for it.
You can download the instructions here.
I didn't bothered making pictures of it, but JunkStyleGio made a render of it: