This vivarium was built in about one day. Basically I piled the Replica Rocks together and using the canned sprayfoam, 'glued' them together and to the glass, resulting in a single large background piece. Then to cover white foam, I applied a layer of brown silicone sealant to the foam matrix and then dusted dry sphagnum peatmoss onto the wet silicone. Allowed this cure and then planted it. You can see a more detailed description of this background method on this tutorial here: Foam, Silicone, Peat Method.
By cutting the a few of the Replica Rocks I was to get the exact shapes I needed for this design. The Flex Resin was able to be cut with a sharp exacto knife in most places and a small hacksaw in a few of the areas on the rocks where the resin was thicker. The backfilled flexible foam made it easy to hold the rocks together as some of them were held in place while the canned spray foam cured by small bbq sticks.
The exact rocks used in this build are the Hawaii Set, a few from the Desert Ledge set, and two from the small medium rock sets.
At this point you can see the silicone and peat has been used to cover up the spray foam. Soil has been added to the bottom and planting has begun.