O = Point(xAxis)
c = Circle(O, 1.0)
A, B = Intersect(c, xAxis)
d = Semicircle(A, B)
M = Point(d)
a = OrthogonalLine(M, yAxis)
b = OrthogonalLine(M, xAxis)
C = Intersect(a, yAxis)
e = Segment(M, O)
f = Segment(M, C)
M' = Mirror(M, yAxis)
h = Segment(M', C)
i = Segment(M', O)
α = Angle(B, O, M)
α' = Angle(B, O, M')