FBm has a jagged trace which resembles the skyline of a mountain range. The clouds, water, and snowline are also modeled with fBm. Note that there is no scientific basis, i.e., linkage to first physical principles, in this choice of terrain models. Mandelbrot and I take a lot of flak for this seemingly ad-hoc approach to modeling Nature. Multifractals FBm is, by design, statistically homogeneous and isotropic.
Real terrains are more complex than that.
Mandelbrot was interested in ameliorating some of the documented artifacts inherent in efficient fBm-approximation algorithms. A multifractal terrain patch. Note the heterogeneity of the terrain. Erosion Some of the most salient features in landscapes are due to fluvial erosion, or running water. These features are formed by drainage of potential from an area, and as such are context-sensitive.