The Outer Circle / Rim and Solid Inner Circle within, represents the 'inner' and 'outer' fighting zones; the 'centre' is you.
It also signifies that you now have some of the wisdom of Patience, Endurance, Humility and proven courage.
Along with the various fighting abilities you have learned by actually asking the Sifu, and Senior Students, (within S.O.M.A), to train you, individually, for each 'Full Contact Combat' grading - which you have passed!
This now gives you, a much better understanding of the 'art' and the School's philosophy, which can, hopefully be applied.
Any Martial Artist, achieving this level, on looking back, will remember something in particular that happened to them, which will be with them for the rest of their lives, even if they give up on the same day they are awarded the Black Belt/Sash, the training and philosophy of that school will stay with them!!!