The Vitruvian Man by Leonardo da Vinci

Besides his interest in art, Leonardo da Vinci studied many subjects that would today be called science. This drawing, completed around 1487, illustrates human proportions first described by the ancient Roman architect, Vitruvius, around 25 BC. Also called the Canon of Proportions, this illustration and the text that accompanies it, describe units, such as the palm ("the width of four fingers") and the cubit ("the width of six palms"), and proportions ("the length of a man's outspread arms is equal to his height"). Note also the text is inscribed using mirror writing.