A river meandering over a noise-based landscape. A line is drawn either horizontally, vertically, or more rarely, a ring. Time progresses for 1,000 iterations as the line travels, bends, and splits.

There is a lot of variation on the line quality - from thin and controlled, to chunky and chaotic. It's a lot of fun to watch it run and see where it ends up.

I've been experimenting with this algorithm for a long time and this is the most visually interesting variation so far.