# Platonic Solids

3 2 Imagine you are on a desert island there are sticks, stones and sheets of bark. If you start experimenting with threedimensional structures you may well discover five perfect shapes. In each case they look the same from any vertex corner point, their faces are all made of the same regular shape, and every edge is identical. Their vertices are the most symmetrical distributions of four, six, eight, twelve and twenty points on a sphere below. These forms are examples of polyhedra, literally many seats and, as the earliest surviving description of them as a group is in Platos Timaeus, they are often called the Platonic Solids. Plato lived from 427 to 347 BC, but there is evidence they were discovered much earlier see page 20. Three of the solids have faces of equilateral triangles three, four or five meeting at each vertex and have names deriving from their number of faces the tetrahedron is made from four, the octahedron eight, and the icosahedron twenty. The 345 theme continues with the common cube, with its six square faces, and the dodecahedron with its twelve regular pentagonal faces. Over the pages which follow we will get to know these striking threedimensional forms better. the PlatonIc SolIdS beautiful forms unfold from unity