Slightly off-topic, but recently I had the thought that it would be fun to implement a hook-and-loop system with the hooks and loops made from heavy guage wire embedded in concrete or welded to steel. Could such a system be strong enough to lift hundreds of tons? Perhaps it could be used to rapidly assemble military infrastructure like bridges or defensive structures--literally velcro the pieces together.
But would this approach be better than other current approaches where things slide together with some simple locking mechanism. And if this hard-core metal vecro worked as well as you hoped, how would you get it apart?
It's hard to beat slapping something together. It might not come apart, or maybe a shape memory alloy could be used for the hooks?