curve distortion to look more like freehand sketch

I have tried to mimic the single stroke effect with grasshopper

https://www.behance.net/gallery/Single-Stroke-mimicry/14936449


, got the size control right and the jitter also , but the spirals still too perfect , can anyone help me to achieve this outstanding results done with processing ?

https://www.behance.net/gallery/Single-stroke/9676863

thanks in advance !