L-systems are formal string rewriting systems introduced in 1968 by the botanist Aristid Lindenmayer to model the growth of plants.
The simplest L-Systems are based on straightforward substitutions.
Here is some historical background.
To generate pictures with L-systems, we need a geometric interpretation of the L-System alphabet.
Here is a gallery of fractals generated by L-Systems.
Bracketed L-systems are a modification by which branching patterns can be generated.
L-Systems can generate Kolams, an type of Indian art.
To be added later:
Context-sensitive L-Systems
Stochastic L-Systems