2D L-Systems — Flat Lindenmayer Turtle Fractals

This is the flat, top-down companion to the 3D L-Systems simulator. It runs the identical Lindenmayer string-rewriting grammar and turtle-graphics interpreter, but draws every segment as a plain 2D line on a flat canvas — no camera, no depth, no orbiting. Pick a preset (Koch curve, dragon curve, fractal plant, Sierpinski triangle and more), or write your own axiom and production rules, then watch the structure grow segment by segment.