I sketched out a design and bought the supplies. I cut the pieces of polystyrene foam and assembled the design with toothpicks, then glued everything, and tried to keep it level.
Then I coated everything with tile grout and sealed it with grout sealant, so it's waterproof.
Here is my current progress...

Tonight I will spray paint it. It will need a few days to air dry before it can go into his tank.
I am really happy with the results so far!
I bought some old rock planters for vivariums at a reptile show a few years ago and will use one for a live plant in his new space. I'm even thinking about changing his substrate to sand, but I'm approaching that decision carefully because I have mixed feelings about using sand for a number of health reasons.
While I've been consumed with this project the dogs have been antsy. My normally lazy and well behaved Osa has turned into a wild frog. Stealing tissues off tables and tearing them up.

Surprisingly Otto just lounges on the couch and sucks his blanket. Yes, I know it's kind of weird. Some dogs do it. He sucks the blanket, makes bread, and occasionally cries into the blanket. It knows all of his secrets.

I should have pictures of the completed project by next week. I'm also nearly finished with my blanket project and looking forward to starting on more gifts for the holidays. I already feel behind on my knitted gifts. Christmas is only 5 months away! Time is short when it takes 2-3 weeks to complete something and I need to get my ass in gear!