This must been done in the forge.
Pile up lots of objects then put a teleport on top, then another crate.
After that delete all of the objects apart from the teleport and the crate on top of the teleport.
Put another teleport on top and make another one of the teleport pads to the one on top of the crate, and have some fun and put some weapons up there.

If you forget to put in the teleport then the crates will collapse.