In this movie (click here or on the image, above, to watch), magnetized liquid iron droplets fall into a pool of silicon oil. The droplets are attracted to the edge of the pool and repel one another. When they fall slowly, the droplets move in precisely opposite directions to one another. But when the speed increases, they move away from one another at the golden angle, ultimately forming spirals. Credit: Douady and Couder
Found in: Numbers