yes like a crayfish condo...
I have about 3 stacks 4 high. I used long wood screws to secure them together in place them cinder blocks to sink them. My thoughts are if you went higher they would inhabit all the tunnel as they can go from level to level.
In fact while snorkeling last Sunday I tried to grab a few big ones and they just slid down to the next level to avoid my hand on the level I was reaching in on.
Oh, BTW....No wetsuit either...water had slight chill but refreshing....
