Leonardo was a mad chef. He enjoyed kitchen contraptions, of his own designs; but, how would it run? “By wind or by water? By cogs and by cranks? By oxen or by peasant-power?” In the late 1490s, most things ran via peasant-power.
Assassin’s Creed did a good job shaping my image of Leonardo; I don’t see him as an old man anymore. Leonardo in the game loves a puzzle, old language and of course, puzzles buried n old language. This blog post on The Kitchen Notebooks of Leonardo da Vinci , HarperCollins Publishers; First Edition edition (April 1, 1987), has also informed that image.