Come to think about it, how do you make a human tower? Aside from the issue of "sliding off" the human below you, how do you get high enough to be able to get on top? I can imagine how you do it for 2 or 3 humans, perhaps more if you use structures to climb higher, but at some point, without support from the map, I can't see how it can be done. For instance, given a map that's just floor and nothing else, how tall could such a tower get?