Figure Derived from Icosahedron. De Divina Proportione (About the divine proportions) is a famous book on mathematics written by Luca Pacioli around 1497 in Milan and first printed in 1509. Today only two versions of the original manuscript are believed still to exist. The subject was mathematical and artistic proportions. The first part, Compendio Divina Proportione, studies and describes the Golden ratio from a mathematical point of view and also studies polygons. The work also discusses the use of perspective by painters. The book contains illustrations in woodcut after drawings by da Vinci. Da Vinci drew the illustrations of the regular solids while he lived with and took mathematics lessons from Pacioli. His drawings are probably the first illustrations of skeletonic solids which allowed an easy distinction between front and back.