A photo of an original page from Leonardo da Vinci's journal, showing the world-renowned drawing known as the Vitruvian Man, created around the year 1492. The drawing and text are sometimes called the Canon of Proportions or, less often, Proportions of Man. Leonardo based his drawing on some hints at correlations of ideal human proportions with geometry in Book III of the treatise De architectura by the ancient Roman architect Vitruvius, thus its name. The accompanying notes are written in mirror writing and describe the drawing as a study of the proportions of the (male) human body as described by Vitruvius.Photo credit: Luc Viatour