n=20 R=60.0: 1817 reachable points (12602 nodes); types: A0:802, A1:211, A2:93, A3:55, A4:47, A5:31, A6:21, A7:21, A8:19, A9:19, A10:19, A11:21, A12:21, A13:31, A14:47, A15:55, A16:93, A17:211   [2.4s]
Lemma 1: K(gamma_B) == type of Def. 2.1 (mod n-2) for 1817 points: failures 0 (non-integer K: 0)   [6.6s]
Descent (Lemma 4b) + invariance of the type under tau_k, mu, rho (Thm 1a): 1817 points, 6894 twist steps (max 29 per point; 3047 landed in the neighbouring corner), every step: shorter, reachable, same type; end = diagonal X_0X_(k+1) with k = type: failures 0   [9.0s]
Conj 2.6: 11109 instances (point, l, eps) with both points inside the disc: failures 0; Conj 2.7 (exact length ratio) on the same pairs: failures 0; 19800 instances with the parallel point outside the disc
Conj 2.6/2.7 by exact ray tracing for all points with |B| <= 30.0: 7449 instances, no short trajectory in the predicted direction within 12|B|+5: 0, type failures 0, length-ratio failures 0   [25.6s]
pairs (u,v), |u|,|v| <= 30.0, det(u,v) = sin(2pi/n) exactly: 311   [25.7s]
   (type u, type v) distribution: {(0, 0): 103, (0, 17): 104, (1, 0): 104}; pairs outside the three classes of Step A: 0
Conj 2.3: reachable n-gons found: 103; with vertex types != (A0,A1,...,A(n-3),A0): 0
   Corollary 3.1 (pair of type (A0,A0) <=> spans a reachable n-gon): failures 0; Theorem 3 (v_1,v_2,v_(n-2),v_(n-1) reachable => reachable n-gon): failures 0; vertices outside the disc decided by exact ray tracing: 4812   [116.6s]
exact fallbacks 46172, mp calls 0
