I have always been delighted by the similarities between the micro and macro levels of the world. A model of an atom reminds us of the solar system’s construction, while the circulatory system reminds us of a system of rivers, and networks of brain neurons look like galaxy clusters. I had painted this abstract background with ink, and I suddenly understood that these accidental ink stains on a small piece of paper looked just like a foggy valley. I added some trees to emphasize the likeness.