Self-Inverses Mark the Universe's Ruler
Z/210Z = DATA ring (subring without L=11). The full Decality has ten terms; OMEGA = D420 marks the boundary. 108 rings share λ=420.
The self-inverse elements of Z/210Z — numbers n where n*n = 1 (mod 210) — are {1, 29, 41, 71, 139, 169, 181, 209}. When used as scale exponents (powers of b=7), they land on physical scales from Planck length to the observable universe. Human scale = E*b = 35 bands. The universe = 71 bands (a self-inverse!).
These 8 elements square to the identity. They are the ring's mirror points — the places where going forward and going backward are the same thing.
Physical scales range smoothly from Planck (10^-35 m) to the observable universe (10^26 m). There's no reason why particular scales should be special. The hierarchy problem: why is gravity so much weaker than other forces? No satisfying answer.
Orders of magnitude = n * log10(7). Self-inverse elements {1,29,41,71,...} mark the universe's natural ruler. Human scale = E*b = 35 (observer * depth). Earth = 42 = THE ANSWER. Solar system = 48 = phi(210). Galaxy = 56. These aren't numerology — they're algebra. n^2 = 1 in the ring.