Leonardo da Vinci obsessed with water more than any of his multidisciplinary interests: architecture, science, painting, and sculpture.
For Leonardo da Vinci, the current represented that perfect chaos that separated air from water. In his Book on Waters, he wrote:
Nothing shares a surface with something and something shares a surface with nothingness. And the surface of something is not part of that thing, whence it follows that the surface of nothingness is part of nothingness, whence it follows that a single surface is the limit between two things that are in contact. Since the surface of water is not part of the water, and hence is not part of the air or of other bodies placed between them, what is it then that divides the air from the water?
Below is one of Leonardo's sketches on the movement of water from 1508. It demonstrates the paradox of water in, around, and again itself.
Writes art historian Irving Lavin, Professor Emeritus in the School of Historical Studies at the Institue of Advanced Study:
…water in percussion: that is, water is itself the obstacle to water, and in this case the contrast is between the resulting currents on the surface, under the surface, and surging upward carrying bubbles of entrapped air. The relationship between air and water, both in combination and as analogous media, was also a subject that greatly preoccupied Leonardo and played a critical role in the development of his thought that concerns me here.
The structure of a stream lies within its anti-structure. There's the unpredictable and disruptive movement of its flow. Yet freshwater slithers over rocks, persisting unperturbed all the way into the mouth of the river.
The chaos of running water seems to be why it works.