Yes, I made a couple of these to transition frags to the main tank. Just black egg crate wire tied together. They are covered in pink algae, for some reason it likes to grow on them. I will take a close up, but a piece of purple tipped acro accidentally touched the back of one of these, now I have that coral growing on the egg crate. Starts as a green hard slime looking material and then one day it starts sprouting little towers. Really neat.