Excellant work, the dual terrain idea has several applications. I've done trees that way too and it works pretty well for the background. There's another trick you can do with the dual terrains. 1. Set up your terrain, then duplicate it. Make the second terain just a fraction of a unit lower than the first, but in the same exact location. 2. Give the second terrain a water texture, or one of those blue stone textures. 3. Use the erode tool on the upper terrain. This is a wip and its overdone, but you get the idea.