A = Point(yAxis)
B = Point(yAxis)
C = Point(xAxis)
c = CircumcircleArc(A, C, B)
P = Point(c)
E = Intersect(xAxis, yAxis)
a = Ray(E, P)
b = OrthogonalLine(C, xAxis)
F = Intersect(a, b)
α = Angle(C, E, P)
G: (y(F), α * y(F) / abs(y(F)))
H: (y(F), 0.0)
d = Segment(C, F)
e = Segment(E, H)
α' = Segment(G, H)