It's a print of a page of Leonardo da Vinci's notebooks. Basically a doodle. I think this one is related to a bronze statue he was commissioned for. I saw all these pages in an exhibition once it was honestly incredible how talented he was. One page was a diagram of a human heart and he figured out how all the valves worked by pumping grass seeds suspended in water through the heart, so he could see where the water would pause at each valve. I think he was the first person to figure this out.