O = (3.98, -1.08)
B = (7.68, -1.18)
c = Circle(O, B)
α = 0.767944870877505 rad (slider from 0 to 6.283185307179586, step 0.01°)
B' = Rotate(B, α, O)
β = Angle(B, O, B')
f = Line(O, B')
B'_1 = Mirror(B, f)
g = Line(B'_1, O)
h = OrthogonalLine(B', g)
C = Intersect(g, h)
i = Line(B'_1, B)
D = Intersect(h, i)