Leonardo wrote a whole collection of notes, Codex Atlanticus, about whirlpools, waterfalls and waves. Wherever he looked, from the motion of water to the ringlets of hair that recur in his paintings, Leonardo saw spirals and curls. Here he hypnotically weaves circular forms into twisting arabesques that cohere in a single vast labyrinth. This design takes an idea basic to his science – that motion tends to the circular – and raises it to a decorative principle that captures the dynamic harmonies of the universe. This is string theory, Renaissance style, or as Leonardo writes in his notebook K: "Proportion is not only found in numbers and measurements but also in sounds, weights, times, positions, and in whatsoever power there may be."

https://www.theguardian.com/artanddesign/interactive/2011/nov/09/leonardo-da-vinci-interactive-guide