Here is a screenshot from the TechNature 2.0 engine. TechNature uses fractal
mathematics to grow random planets, trees, and grass. The planet is
different every time you run the program. It takes few minutes to calculate
the 4 billion multiplications required to generate all of the polygons, and
over 3mb of procedural textures. One of the new features is terrain shaping.
Despite a completly random surface, terrain shaping allows for a custom flat
playing surface. Perfect for vehicles that dont like mountains! Screenshots,
and the 1mb demo can be found at http://www.tanzanite.to/