3d fractal automata

[Tglad]

And here is trees2.es9 from the top and from the side.
These examples are in the zip file, on the original link.

[Tglad]

Once you have found nice rules, they can be put into a level with perspective. The levels-of-detail let you deal with objects close up and far away. Here I have applied the 'arid' rule to a course grid of hills with tree shapes on them:

[Tglad]

Same level with the trees rule applied. Notice that normals and shadows aren't enough to get a good 3d feel, probably ambient occlusion would be needed:

[Tglad]

And lastly, the course grid that they are based on, which is user-built:

[kram1032]

Nice stuff that gave me an idea:
Since voxelized Mandelbulbs are readily available, you could try to use one of those as a base.