Information on L-Systems in available on the Wikipedia article on L-Systems.
I cannot usefully describe a fractal in words, so there is no alternate text on these images.
The L-Systems were created using Haskell and the HOpenGL library. The source code is available. To run it, I used Hugs; you will required the HOpenGL library which can be downloaded from the Haskell website (if you don't have it already). Run the program in Hugs (e.g.
hugs -h50M LSystems.hs) and type
main 1 to draw system 1, systems 1 to 9 are defined.
I advise first-year Imperial Computing students not to look until after their coursework is submitted. If you do, remember to cite this web page as a source when submitting your coursework! (You could do this by writing a comment in the source file like "I don't understand what this does, because I just copied it from http://matt.blissett... instead of asking for help when I needed it" etc.)
At the moment the L-systems are quite basic, I'm working on adding three dimensional systems and probabalistic rewriting, and anything else I find interesting.