P to pause/resume SPACE to hide/show variables. Colour Mode: 0= real colour 1=bizzaro colour Colour: You can offset the colour on each brushstroke using this slider. Here I use a stamped brushstroke to create the likeness of the NPR guy. You can change the colour mode and offset as well as the brush size and style to suit your liking.
Edge tangent field by @gtoal. hacked effect blocks to work around stage3D bug by @xlk: https://scratch.mit.edu/projects/12392264/