n=13: 823 reachable points of length <= 40, 192 classes of parallel directions
  class of alpha=2.644212: floating billiard finds 6 of the 6 (length, factor) pairs of the unfolding, none else
  class of alpha=2.636898: floating billiard finds 6 of the 6 (length, factor) pairs of the unfolding, none else
  class of alpha=0.942413: floating billiard finds 6 of the 6 (length, factor) pairs of the unfolding, none else
  class of alpha=1.007906: floating billiard finds 6 of the 6 (length, factor) pairs of the unfolding, none else
  class of alpha=0.079188: floating billiard finds 6 of the 6 (length, factor) pairs of the unfolding, none else
  class of alpha=1.300802: floating billiard finds 5 of the 6 (length, factor) pairs of the unfolding, none else
bands computed: 8404 (rays from O, both sides); largest number of segments of a simple preclosed piece: 110
odd n: in every class exactly m = 6 preclosed lengths c*lambda*sin(2j pi/n)/sin(pi/n), factors d_j = n'/gcd(n',j); classes by n': {13: 176, 1: 16}
  n'=13: factors 13,13,13,13,13,13  gcd 13  a quotient is n: no  classes: 176
  n'=1: factors 1,1,1,1,1,1  gcd 1  a quotient is n: no  classes: 16
DONE n=13 [6.9s]
