Leonardo da Vinci , the famous Italian polymath who painted the Mona Lisa , had a sophisticated geometric understanding far ahead of his time. To draw the Vitruvian Man in 1490 – an illustration of the 'ideal' human body – the Renaissance artist may have relied on a mathematical ratio not formally established until the 19th century. It's one of the most iconic images of all time, and yet for more than 500 years, no one could decipher why da Vinci chose such specific proportions for the arms and