London dentist Rory Mac Sweeney has discovered the solution to a five-century-old mathematical mystery hidden in Leonardo da Vinci's famous drawing of the Vitruvian Man.[1] In his study published in the Journal of Mathematics and the Arts, he identified a hidden equilateral triangle between the figure's legs that da Vinci noted in his notes.[1] This triangle corresponds to the Bonwill triangle, an imaginary geometric form used in dentistry to describe the optimal function of the human jaw.[1] Analysis showed that using a triangle in the drawing produced a ratio of 1.64 to 1.65 between the side of the square and the radius of the circle, which is very close to the number of 1.633 found in nature when building the most efficient structures.[1] Mac Sweeney suggests that this is a deliberate solution and that da Vinci had a perfect understanding of the ideal design of the human body long before modern science.[1]