===Making plants grow towards light=== Using lindenmayer systems and genetic algorithms to simulate plant growth. Plants are given a "fitness" based on their leaves - * How much do they face the light? * Are they too close to other leaves? * Are they in shadow from another leaf? * Are they below the ground? * The fitness drops as the plant description (a linenmayer system string) gets too long. {{http://www.pawfal.org/dave/images/patab-angle-s.png}} {{http://www.pawfal.org/dave/images/patab-close-s.png}} {{http://www.pawfal.org/dave/images/patab-occlude-s.png}} The leaf score is indicated by it's colour (red=bad, green=good). Using this measurement, a genetic algorithm can create populations of individual plants, score each one and iteratively create new populations by combining fit individuals.

The simplest strategy is to "cheat" with one leaf :) Each frame is the fittest of a new population, the text is the current lindenmayer string. {{http://www.pawfal.org/dave/images/patab-long.png}} The result of a long run with many thousands of generations. Many leaves circle the light to get the maximum photosynthesis possible. {{http://www.pawfal.org/dave/images/patab-helped.png}} You can also evolve from a starting point - in this case a simple tree is modified to create a bigger and more suitable one for the environment. Code: http://www.pawfal.org/flotsam/jetsam/patabotany/scheme/

Another evolutionary run, a bit more interesting than the one-leaf approach.