Challenge: 3D Fractal Terrain Generation using the "Diamond Square" Algorithm

[Diamond Square](https://en.wikipedia.org/wiki/Diamond-square_algorithm) is an efficient and often used algorithm to generate realistic looking terrains for games etc.

What I mean by "3D" is that you have a 2D array (x-y coords) and then generate a so-called "heightmap", basically the z-coord. This coord can either be used for giving tiles colors or generating mountains or smth like that.