An L-system or Lindenmayer system is a type of formal grammar that can be used to generate self-similar fractals. This application uses JavaScript and the JSXGraph.js library to execute various L-systems and create an image using turtle graphics.
Next table shows the meaning of the characters used in the axiom and rules:
| F | Turtle moves forward and draws a line |
| f | Turtle moves forward without drawing |
| A...Z (except F and only capitals) | Parameters used in the evolution, but without any turtle action |
| 1 | Deleted in every iteration, except in the end where it represents F |
| + | Turtle turns left |
| - | Turtle turns right |
| | | Turtle turns around (180 degrees) |
| [ | Remember current position and angle (and add to stack) |
| ] | Return to last stored position and angle (and delete from stack) |