The Platonic Solids

The Platonic solids are regular 3-D figures. Regular means that all the edges are of equal length, all the angles of equal measure, and all faces are congruent shapes. The solids were discovered by the Pythagoreans but later described by the Greek philosopher Plato.
Tetrahedron Hexahedron Octahedron Dodecahedron Icosahedron
Made of 4 equilateral triangles Made of 6 squares Made of 8 equilateral triangles Made of 12 equilateral pentagons Made of 20 equilateral triangles
Smallest volume for its surface Commonly called a cube Rotates freely when held by two opposite vertices Largest volume for its surface area 

Images by Rüdiger Appel