I believe the choice of Porphyry in the portrait group of tetrarchs speaks to imperial power. Portrait of the Four Tetrarchs is a porphyry sculpture group of four Roman Emperors dating from around 300 AD. The sculptural group has been fixed to a corner of the facade of St mark's Basilica in Vence, Italy since the Middle Ages.
One is that the earth is shaped as a circle and two is that it is shaped as a square
6. gravity
7. gravity
8. not change, but my weight would be less.
