These hills were made from pink foam and suite my modular demands on the tabletop. They were cut out with a hot foam cutter; textured on the sides and top by taking a broken cinder block and bashing in the textures; followed by a standard drybrushing of greys and a little tan and brown before the lightest grey. Really easy and a technique from DM Scotty.
Sadly, I think they may look a little nicer with addition of sand to the top of each piece. Oh well.
The Idea behind these hills is that they can be used as elements in a large array of settings, as well as create very different features by combining the pieces in different ways.
Small dungeon layout, I guess I should get a copy of into the breeding pits.