I would love to make one of these cakes (not so tall though, maybe 2-3 tiers). how do they get the boxes stacked like this and not have them fall? is there pvc pipe going through them? how would the top cake not rip off of it if so? i love doing cakes and would love to make one as awesome as this

Definitely a center anchor point of some sort, with hidden "shelves" that the tiers are sitting on. So there's no fear of anything ripping off, remember it's just an illusion of instability and that they could come topping down at any time.

thanks! one day i'll be able to make one of these lol