Seems like a regular challenge and something done in many designs, but haven't seen good advice on how to do it.
I'd like the surface of the outworld to be covered in sand, and look like regular sand, but the ants shouldn't be able to move it. Ideally the method should also allow for some sort of sculpting of the surface.
I'm guessing some of you pour plaster or grout into the outworld, then cover it with sand while it's still wet. How happy are you with this approach? Does the sand cover the surface completely once the loose grains are shaken out? How do you shape the surface, since it's not very shape-able when wet, and you can't use tools afterwards since the sand only covers the surface?
Any other ideas? Some kind of sand dough, which would have sand throughout the volume and be sculptable? Sticking the sand to the surface of plaster/grout post-sculpting, with some ant-friendly glue?
Any tips very appreciated : )