grass generative wisp like l-system mathematical model

template design graphic texture background pattern concept abstract vector fractal computer generated generative self-similar rewrite self-similarity self-contacting binary recursion endless repeating iteration l-system lindenmayer system curve graph curvature figure branching branched truncated tree plant weed herb grass inflorescence panicle whisk wisp tree-like dendritic arborescent dendriform dendroid arboraceous dendritical