A = (0, 0, -1)
B = (0, 0, 1)
rayon1 = 0.8 (slider from 0 to 6, step 0.1)
rayon2 = 1.6 (slider from 0 to 6, step 0.1)
a = Sphere(A, rayon1)
b = Sphere(B, rayon2)
c = IntersectConic(b, a)
C = PointIn(b)
d = Segment(B, C)
e = OrthogonalPlane(C, d)
M = PointIn(e)
f = Segment(M, C)
α = Angle(M, C, B)