From Leonardo's passing mention about beginning “the two Virgin Marys” and his copious drawings that often include sketches for several projects on one sheet, one can fairly presume that he liked to work on several things at once. This may have been partly owed to his obsessive nature and been partly a habit he picked up from Verocchio, who, we know, enjoyed moving back and forth between concurrent projects. Along with the Benois Madonna, Virgin and Child with the Cat, Portrait of Ginevra de’ Benci, and, possibly, the Bust of Christ, Leonardo probably devoted some time in the very late 1470s, and more focused attention in the early 1480s, to the conception of a nursing Madonna in profile, known from a quick sketch on a sheet at Windsor (c. 1478–79), which shows Mary both full-face and in three-quarter view (fig. 3); an exquisite, metalpoint study for the Virgin's head (c. 1481; fig. 52); and a workshop picture, often attributed to his follower Giovanni Antonio Boltraffio (fig. 53).