The two figure-8 shapes which have been drawn there are known astronomically as "analemmas".Each figure-8 shape represents the location in our sky of some nearby astronomical object (say Sun or Moon), when viewed at the same time each day over the course of an entire year.That is also why a broad outer circle which represents Earth's annual orbit about the Sun was drawn there: in order to emphasize "one full solar year" of four seasons (light for six months of summer, then dark for six months of winter). 4 circles can be view in the back. An analogy can be drawn with the four elements (fire, water, wind, earth). a broad outer circle which represents Earth's annual orbit about the Sun was drawn here: in order to emphasize "one full solar year" of four seasons. There is one more symbol very big... i let you find it ...