L-Systems

Fractal Tree: (F -> FF+[+F-F-F]-[-F+F+F] 25°)
Hilbert: (A -> (-BF+AFA+FB-), B -> (+AF-BFB-FA+) 90°)
Sierpinski triangle: (F -> (G-F-G), G -> (F+G+F), 60°)
Koch curve: (F -> (F-F++F-F), 60°)
Dragon: (X -> (X+YF+) , Y -> (-FX-Y) 90° )
Quadratic: (F -> (F+F-F) 90°)
32-segment curve (F -> (-F+F-F-F+F+FF-F+F+FF+F-F-FF+FF-FF+F+F-FF-F-F+FF-F-F+F+F-F+) 90°)
Arrowhead curve (X -> (YF+XF+Y), Y -> (XF-YF-X) 60°)
Peano-Gosper curve (X -> (X+YF++YF-FX--FXFX-YF+), Y -> (-FX+YFYF++YF+FX--FX-Y), 60°)
Peano curve (F -> (F+F-F-F-F+F+F+F-F), 90° )

Reference: http://mathforum.org/advanced/robertd/lsys2d.html

Demo: https://anshikakaythwas.github.io/L-Systems/