I have a large hammer coral that has been living on an eggcrate shelf for the last couple of years. You couldn't really see the shelf itself because the coral is so dense, and the egcrate was black. I had to rebuild it due to the shape of the old shelf and the growth of the turbinaria in front of the hammer. I wanted it to give the illusion of the coral growing on a rock shelf as opposed to the "floating" effect it had originally. I made it out of eggcrate and colored epoxy. Here's how it turned out, I'm pretty happy with it.
FTS:
A closer look:
Before it went in the tank:
The support system made with eggcrate brackets with sure grip magnets:
FTS:
A closer look:
Before it went in the tank:
The support system made with eggcrate brackets with sure grip magnets: