When Did Plato Discover The Platonic Solids?

When Did Plato Discover The Platonic Solids? These solids were introduced by Plato in his work Timaeus (ca. 350 BCE ), in which all then known forms of matter—earth, air, fire, water, and ether—are described as being composed of five elemental solids: the cube, the octahedron, the tetrahedron, the icosahedron, and the dodecahedron. Are platonic