n=15: 825 reachable points of length <= 40, 181 classes of parallel directions
  class of alpha=0.196937: floating billiard finds 7 of the 7 (length, factor) pairs of the unfolding, none else
  class of alpha=0.398595: floating billiard finds 7 of the 7 (length, factor) pairs of the unfolding, none else
  class of alpha=2.491381: floating billiard finds 7 of the 7 (length, factor) pairs of the unfolding, none else
  class of alpha=0.664469: floating billiard finds 7 of the 7 (length, factor) pairs of the unfolding, none else
  class of alpha=2.578964: floating billiard finds 7 of the 7 (length, factor) pairs of the unfolding, none else
  class of alpha=0.068360: floating billiard finds 7 of the 7 (length, factor) pairs of the unfolding, none else
  class of alpha=0.344936: floating billiard finds 7 of the 7 (length, factor) pairs of the unfolding, none else
  class of alpha=2.595295: floating billiard finds 7 of the 7 (length, factor) pairs of the unfolding, none else
bands computed: 9360 (rays from O, both sides); largest number of segments of a simple preclosed piece: 106
odd n: in every class exactly m = 7 preclosed lengths c*lambda*sin(2j pi/n)/sin(pi/n), factors d_j = n'/gcd(n',j); classes by n': {15: 116, 5: 38, 3: 22, 1: 5}
  n'=15: factors 15,15,5,15,3,5,15  gcd 1  a quotient is n: yes  classes: 116
  n'=5: factors 5,5,5,5,1,5,5  gcd 1  a quotient is n: no  classes: 38
  n'=3: factors 3,3,1,3,3,1,3  gcd 1  a quotient is n: no  classes: 22
  n'=1: factors 1,1,1,1,1,1,1  gcd 1  a quotient is n: no  classes: 5
DONE n=15 [6.4s]
