A = (2, -1)
B = (3, 1)
a = Segment(A, B)
C = (1, 1)
b = Segment(A, C)
S = (2, 3)
c = Segment(A, S)
D = (5, -1)
E = (9, -1)
d = Segment(D, E)
F = (6, 1)
e = Segment(D, F)
G = (7, 5)
f = Segment(D, G)