Leonardo da Vinci had such a playful curiosity. If you read his notebooks, you'll see he's curious about what the tongue of a woodpecker looks like, but also why the sky is blue, or how an emotion forms on somebody's lips. He understood the beauty of everything. I've admired Leonardo my whole life, both as a kid who loved engineering - he was one of the coolest engineers in history - and then as a college student, when I travelled to see his notebooks and paintings.