Lindenmayer system, or L-System, was introduced in 1968 by the biologist Aristid Lindenmayer, primarily conceived as a mathematical theory on plant development. In the 'bible' of L-Systems, "The Algorithmic Beauty of Plants" (ISBN 0-387-97297-8) - or ABOP for short-, Lindenmayer and Prusinkiewicz wrote:
- "The central concept of L-systems is that of rewriting. In general, rewriting is a technique for defining complex objects by successively replacing parts of a simple initial object using a set of rewriting rules or production."
An l-system is a rule like description of a 3d form. It contains descriptions of parts and how they should be assembeld together.
The description is applied to itself a number of times (e.g., recursion levels) so fractal and recursive forms are very easy to describe in an l-system. That's why they are used a lot for plants and natural looking organic forms. By increasing the recursion level the form slowly 'grows' and becomes more complex.