It came from Zefrank's The Scribbler

It looks like ZeFrank's web site has gone to 404. It could be that there are no longer any copies of the swf program for the Scribbler hosted anywhere. (Unless via the Wayback Machine?)

Cartoon horse getting up.

Same general approach as with the skeleton, with slightly less transparency to bring out the individual colours, but enough to show details.

With a combination of high degree of transparency and minimum randomness, details emerge.

Blue, green and a touch of red.

Making use of the colour choices.

I used a bucket fill tool to swap in yellow in lieu of the usual Scribbler white 'canvas'.

When horses figure out tandem bicycles, they're going to win all the jerseys.

The Scribbler gizmo works on a white canvas. I can change that by having lines everywhere on the canvas or by painting over the white areas after the fact with some other art program. This year I'm trying something else: flipping the image into a negative. That gives me a black background, good for night skies that bleed nicely into the low opacity scribbles. I just have to choose the negative equivalents of the colours I want to have appear in the final image. I eyeballed a few telescope images of this nebula to dot in the stars at about the right spots.