Lazy-quadtree

From Picogen-doc

Currently the mightiest object: It represents a "2.5 dimensional" terrain; that is, it represents 3d terrain, but without overhangs.

The terrain-formation is described by a little program, which is not too hard to learn, but probably irritating to non-programming folks (but the dev-team is also working on solutions which build on that programming language, but don't require any programming).