Fig. 4a. The icosahedron can be constructed analogously to the dodecahedron. First generate three rectangles whose sides are 1 and f (the green rectangles in this figure). Then place these within the cube, as was done for the dodecahedron, but ignore the cube and connect the twelve vertices, in order to form the triangular faces of the icosahedron. | Figure 4b | back to text |