I work as a painter, draughtsman, engineer, scientist, theorist, sculptor and architect, and I keep notebooks that join art and science across anatomy, astronomy, botany, cartography and painting.
With permission to dissect at Santa Maria Nuova in Florence and later in Milan and Rome, I made more than 240 detailed anatomical drawings and about 13,000 words toward a treatise on anatomy.
In the Mona Lisa I developed sfumato, "Leonardo's smoke": oils blended on the surface so no brushstroke shows, with shadowed corners of mouth and eyes that leave the smile unresolved.
In 1502 I made a town plan of Imola that won me the post of Cesare Borgia's chief military engineer and architect, then a map of the Chiana Valley for his strategic position.
Studying perpetual motion, I concluded it was impossible and in 1493 wrote down laws of sliding friction in my notebooks, two centuries before Guillaume Amontons rediscovered them in 1699.
For the refectory of Santa Maria delle Grazie in Milan I painted the instant after Jesus says "one of you will betray me", designing each disciple's reaction as art built from expression and gesture.
I gathered my notes on anatomy, light and landscape as material for a series of treatises, so that painting could be taught as a science built on the study of nature.
I drew machines the way I drew bodies, producing the first form of the modern technical drawing and a perfected exploded view that shows internal components; my engineering studies fill over 5,000 pages.
In Milan I painted the Virgin of the Rocks for the Confraternity of the Immaculate Conception: four figures in a wild landscape of rock and water, finished in two versions.
For Ludovico Sforza I designed an equestrian monument to Francesco Sforza larger than Donatello's Gattamelata or Verrocchio's Colleoni, completed the model and planned the casting in detail.
My science works by observation: I try to understand a phenomenon by describing and depicting it in the utmost detail, rather than leading with experiments or theory.
I kept daily notes and drawings, about 13,000 pages fusing art and natural philosophy, mostly in mirror-image cursive; they now sit in the Codex Atlanticus, the Codex Leicester and major libraries.
