Regular polyhedra, c 1650-1691.
© Science Museum / Science & Society Picture Library
These are three of the five skeletal polyhedra asociated with the physicist Robert Boyle (1627-1691). They have been extensively restored. Since ancient times it has been known that there are only five regular polyhedra: three-dimensional figures which appear the same when viewed from any angle. These, from top to bottom, are an icosahedron, a dodecahedron and a cube.