Those finest lines on the left of the image, especially the bottom half, started with a completely black area, working with a “white” or “colorless”, which in digital terms is identical, pen, mostly one-pixel, being the finest possible. Such structures for example are completely beyond any capabilities computers have in generation of such things, because there complexity is in principle way beyond even natural structures too. Computers have the hardest time to come even close to the latter. But the aesthetic feedback loop of hand and eye, connected by a human brain, being able to act at will (!) is simply in another ballpark, and it is only a question of one’s creativity what comes about, like with any other improvisation.