1 Observations on the geometry behind the design of the ‘Vitruvian Man’ by Leonardo da Vinci Leno L. Mascia Loughborough University, Loughborough, UK. 1. Introduction The drawing with the title Proportions of the human body according to Vitruvius by Leonardo da Vinci (1490), located in the Gallerie dell’ Accademia in Venice (Italy), is a good example of the use of quantitative design parameters in the execution of works of art. Scholars from a variety of disciplines, particularly from the architects’ community, have been drawn the attention to Leonardo’s anthropometric parameters displayed by the man in the square and have debated on issues surrounding the golden section to determine the ratio of the side of the square (the height of the man in the standstill position) to the radius of the circle (the circumscription of the man in raised-arms and open-legs posture). Other important geometric features, such as the asymmetry inherent to the posture of the man in the circle, have so far not been addressed in an analytical and quantitative manner. From the very early stages of my research on Leonardo’s Vitruvian man it became obvious that the literature had not paid attention to the ‘oddity’ of the posture of the legs. This feature became particularly attractive to me alongside the positioning of the extremities of the limbs inside the circle [1]. 2. Origin of the Vitruvian man In the Ten Books on Architecture (ca. 25 BC) the Roman architect Marcus Vitruvius Pollio draws attention to symmetry in the design of Temples (Book III, Chapter 1), which should reflect the proportionality of members of the human body represented by the forearm (cubit), the palm and the finger (digit) and the foot. Vitruvius states that the navel is naturally placed at the centre of the human body: ‘For if a man be placed flat on his back, with his hands and feet extended, and a pair of compass centred at his navel, the fingers and toes of his two