The Pentagon  
The pentagon is a 5 sided figure (Penta meaning 5.) It is seen in the painting as the surface of the dodecahedron which is one of the Platonic solids. The famous building, the pentagon which is the seat of government in the USA is built in this shape. Inscribed within is the 5pointed star, a pentagram, frequently seen in military ensignia. Superimposed on this pentagram is a golden proportion gauge showing a smaller to larger division of the Golden Proportion on a line (a chord) of the pentagon as seen below. 



Pentagon, 5 Pointed Star 

The ancient Greeks, starting with Pythagoras in about 550 BCE, were very interested in the way the the diagonals
of the pentagram (the 5 pointed star) intersect each other in the golden proportion and gave the first formulation
of the golden proportion in the following terms. 