This perfect glint of luster—the white sparkle caused by a light hitting a smooth and shiny surface—was another of Leonardo’s signature marks.

The water flows from the heavens and distant lakes, cuts through rocks to form dramatic cliffs and smooth pebbles, and pours from the cup of the Baptist, as if connecting to the blood of his veins. Finally, it swaddles the feet of Jesus and ripples to the edge of the picture, reaching us and making us feel a part of the flow.

The fifteenth century of Leonardo and Columbus and Gutenberg was a time of invention, exploration, and the spread of knowledge by new technologies. In short, it was a time like our own. That is why we have much to learn from Leonardo. His ability to combine art, science, technology, the humanities, and imagination remains an enduring recipe for creativity. So, too, was his ease at being a bit of a misfit: illegitimate, gay, vegetarian, left-handed, easily distracted, and at times heretical. Florence flourished in the fifteenth century because it was comfortable with such people.

I also discovered, at first to my consternation and then to my pleasure, that Leonardo was not always a giant. He made mistakes. He went off on tangents, literally, pursuing math problems that became time-sucking diversions. Notoriously, he left many of his paintings unfinished, most notably the Adoration of the Magi , Saint Jerome in the Wilderness , and the Battle of Anghiari . As a result, there exist now at most fifteen paintings fully or mainly attributable to him. 16

I did learn from Leonardo how a desire to marvel about the world that we encounter each day can make each moment of our lives richer.

The reason he wanted to know was because he was Leonardo: curious, passionate, and always filled with wonder.

Paper turns out to be a superb information-storage technology, still readable after five hundred years, which our own tweets likely won’t be.