This sim treats each of the colour channels of the image as a separate fluid component which is immiscible with the others. Here the blue and green repel each other strongly, but the red only interacts weakly with the others.
I'm having fun exploring the parameters space of the sim, but it's big, and has a lot of dead ends. Many, perhaps most, combinations are uninteresting, though you get nice surprises like this. The problem is that there are about 7 or 8 parameters to play with, and each of them can range over many orders of magnitude, and then some behaviour will emerge for a certain range, but it will be highly sensitive to one or two parameters just inside some tiny range. Interesting, challenging.