Can I make caves with egg crate?

I am brainstorming a little and I was thinking about buying egg crate and cutting it up and using zip ties to make a space and or spaces under the live rock. I know people use it to raise rock slightly off the bottom of the tanks but i am thinking on a bigger scale. Anyone ever do it of have any ideas about it?

 

people do this often, or with pvc pipe and zip ties.

 

Egg crate zip tied together works good for me, but if you want it to be sturdy use PVC with it then zip tie the egg crate to it. I built this with egg crate.
Good luck and have fun.;D

 

made 2. and i figured i would put up some pics so people can see first one is in the tank and here are a couple pics of the second.