Rocks:

Check out a mesh rock compared to an ordinary sculpted rock. It's my first mesh creation. Soon my vastly superior mesh products will completely dominate the market for rocks. O.o

The mesh rock has a land impact of only one prim and you can stand on it. Observe what happens when I try to stand on the sculpted rock (bottom photo). I sink right through it. You can walk through sculpted rocks, but not mesh rocks. Mesh rocks however, increase in land impact with size. So if the mesh rock was re-sized large enough, it would have a land impact greater than one. Sculpts don't increase in land impact with size.