Genius animator Joaquin Baldwin, whose 3D-printed projects I've featured here before, says:
For the fans of the Portal games, this is the latest 3d-printed weirdness I made, a puzzle box. It was much harder than I expected, went through 2 prototypes to get it to work out, and I still had to fix a lot of things with a knife and sandpaper to get this model to work just right. Not for sale though, unless you wanna do the delicate carvings to fix it yourself :)