for the walls i got some large styrofoam pieces about an inch and a half thick from some construction site. I cut them up and used toothpicks to stick pieces together. Then i got some self-sealing tile grout (a small bucket) and smeared it all over. I was hoping it would be a little darker, but i'm still happy with it. If you noticed the one shelter in there, it is made with styrofoam and the extra grout i had, also. Nice leos.
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Paullywog

Nobody's perfect. I'm nobody, so I'm perfect.