A = (4, -1)
B = (8, -1)
c = Circle(A, B)
α = 2.9115582581769406 rad (slider from 0 to 6.283185307179586, step 0.01°)
M = Rotate(B, α, A)
β = Angle(B, A, M)
d = Circle(B, M)
f = Line(A, M)
B' = Mirror(B, f)
g = Line(B', M)
C = Intersect(d, g, 2)