The M87 (EHT2017) black hole images indicate a dodecahedral structure of the gravitational singularity. One feature in the final image sequence of the black hole shadow is standing out. It is the nearly perfect pentagonal shape of the ring structure and the existence of five knots in this ring-structure ! If these five knots turn out to be real and stable, then we may look at a gravitational singularity which indicates a more complex universe then expected ! The pentagonal ring structure may indicate a Poincare Dodecahedral Space (PDS) structure of our universe, and a dodecahedral shaped gravitational singularity (black hole) in the center of M87. Further evidence comes from the contrast- and brightness-enhanced image of the black hole shadow presented in the EHT2017 documentation “Black Hole Hunter”. This image indicates a lattice of 3 to 4 full pentagonal rings and 4 to 5 pentagonal-shaped rings, which are only partly visible. Only the brightest ring in the image was presented to the public as the M87 central black hole ! This lattice of pentagonal rings may be a projection of the assumed dodecahedral structure of the black hole onto the surrounding transparent emission region, caused by photon capture and gravitational light bending around this dodecahedral gravity source. The EHT2017 images may provide evidence for the underlying universal theory of our universe Albert Einstein was searching for. Albert Einstein had a universal theory in mind, where physics is reduced to geometry, based on natural constants like Pi and e, constants which are all transparent constructions out of number 1. ( --> see Albert Einstein’s letter from 13.10.1945 in Chapter 6 ) With the help of the study “Phase spaces in Special Relativity : Towards eliminating gravitational singularities” I found a way to express all natural numbers and their square roots only by using constant Phi (ϕ) and number 1. Constant Pi (π) can also be expressed by only using the constant Phi and 1 !