Drawing of Two Heads in Profile and Studies of Machines

A single sheet, dated to the end of 1478, holds two very different things at once. On one part an old man and a young one face off in profile, the old one's nose and chin pushed out until they nearly meet, the youth beside him smooth and ideal. It is among the earliest of the grotesque heads Leonardo would keep drawing all his life. Around and behind them he has sketched gears and mechanical parts, one big cogwheel cutting straight across the back of a head. And in a line of his mirror writing the sheet records something private: that in December 1478 he had begun two paintings of the Virgin Mary. Faces, machines and a working diary note all share the same page.