Kepler's polyhedra, 1619.
© Science Museum / Science & Society Picture Library
Engraving of 'Archimedian Solids' including a truncated icosahedron, from 'Harmonices mundi' (The harmony of the world) by German astronomer Johannes Kepler (1571-1630) published in Linz, Austria in 1619. In this section Kepler gives the first complete description of convex uniform polyhedra. In the book Kepler announced his third law of planetary motion, stating that the square of a planet's periodic time is proportional to the cube of its mean distance from the sun. Kepler's three laws formed the basis of Isaac Newton's discoveries. Wilhelm Schickard designed the woodcut diagrams and illustrations for this work.