A = (-3, 3)
B = (1, 3)
a = Segment(A, B)
b = LineBisector(a)
S = Intersect(b, a)
c = Semicircle(A, B)
C = Point(c)
d = Segment(C, A)
e = Segment(C, B)
α = Angle(A, C, B)