License, verbatimCC0
The Metropolitan Museum of Art: Open Access, Creative Commons Zero (CC0). Flagged isPublicDomain=true in the museum's own record.
Stefano della Bella. Plate 3: Six eyes, three ears, two profiles, and a mouth, from "The Book for Learning to Draw" (Livre pour apprendre à dessiner), ca. 1649. The Metropolitan Museum of Art.