evolution to a sculpted rock

This terrarium started off as fiberglassed insulating foam board. We painted the glasswork with camo spray paints (khaki and olive drab). That seemed too dull, so, we decided to add some fake rock background.
Spray foam (Great stuff) on the back & side walls, as well as the corners to get most of the shaping. Eventually, I stood the terrarium up, and let gravity sculpt the great stuff a bit. Added tile grout to the whole surface (forget spatulas & brushes; grab gloves & go to town). Then, after the grout cures for a week, you can add the primer. I higly recommend this, as it will give an undercoating to the textured paint and add a little depth. We used the rust red rustoleum primer & then went over that with the green granite-textured fleckstone paint. Once that dried, we brushed over it with grout sealer & let that cure...