- https://github.com/rafrex/fractal/blob/gh-pages/app/fractal.js
- http://www.kevs3d.co.uk/dev/lsystems/#
- Asynchronous recursion: http://mostafa-samir.github.io/async-recursive-patterns-pt2/
- Graphical modeling using L-Systems: http://algorithmicbotany.org/papers/abop/abop-ch1.pdf
- https://eng.qualia.com/drawing-fractals-in-the-browser-with-l-systems-and-es6-6cecfd74e084
- Function parameters via properties: http://stackoverflow.com/a/8510580