The L-System Lab 2D is a one-page JavaScript application which allows for creating SVG graphics based on grammars and turtle graphics.
The best way to understand the application is to read the book by Przemyslaw Prusinkiewicz and Aristid Lindenmayer: The Algorithmic Beauty of Plants which is available as pdf on the Internet.
The book is also in the ACM Digital Library with a BibTex entry but no download:
@book{10.5555/83596,
author = {Prusinkiewicz, P. and Lindenmayer, Aristid},
title = {The algorithmic beauty of plants},
year = {1990},
isbn = {0387972978},
publisher = {Springer-Verlag},
address = {Berlin, Heidelberg}
}
While Prusinkiewicz' and Lindenmayer's intention is to model plants, the intention of this project is only to create 'cool graphics'.