a = 0 (slider from 0 to 5, step 1)
A_{1} = (11.92, -14.06)
B = (27.12, -11.12)
f = Line(A_{1}, B)
S_1 = (13.8, -4.62)
D = (18.12, -10.2)
k_1 = Circle(S_1, D)
A = Point(f)
C = Point(f)
c = Circle(A, C)
d = Mirror(k_1, c)
g, h = Tangent(f, d)
k_2 = Mirror(g, c)
k_3 = Mirror(h, c)
S_3 = Center(k_3)
S_2 = Center(k_2)