Amazing algorithm-based patterns by Anders Hoff.
“The Differential Line algorithm is inspired by the way a number of biological things in nature grows. Among other things it is made to mimic the growth of the human brain, as well as a great number of plants. In brief; we start of with a number of connected nodes in a circle. Gradually we introduce new nodes on the line—prioritizing segments where the curve bends more sharply. Over time the curve grows increasingly intricate, but it never self-intersects.
Differential Mesh is an extension of the Hyphae algorithm. I started working on it with the intention of mimicking the growth of certain types of lichen. The results, to me, are equal parts crystal-like and biological. Hyphae is an algorithm I wrote in an attempt to mimic the growth of roots. You can see a video of how the algorithm grows here. The algorithm centers around letting circles grow "next to each other" in such a way that no two circles overlap. The results are incredibly intricate and fractal-like, and they can be tweaked in a great number of ways.”
(Source: http://inconvergent.net/)