while browsing i found this step by step tutorial about differential growth in processing.
https://medium.com/@danefilipczak/node-based-differential-growth-tutorial-d5287d7c3c86#.nbpputtyr
so i gave it a shot in VL and it only took about 2 hours to get it running and another hour to beautify the patches. the node names are the same as in the article so that if you are interested, you can compare the patches with the code.
Differential Growth.zip (25.8 KB)