S_1 = (6.7388, 2.1812)
B = (8.65759307184692, 3.1044928714564564)
k_1 = Circle(S_1, B)
S_2 = (7.68, 1.98)
D = (3.44, 2.22)
k_2 = Circle(S_2, D)
a = 0 (slider from 0 to 5, step 1)
C = (9.93268379206782, 1.2054215860210742)
A = Point(k_1)
ω = Circle(A, C)
d = Mirror(k_2, ω)
E = Intersect(k_1, ω, 1)
F = Intersect(k_1, ω, 2)
f = Line(E, F)
g, h = Tangent(f, d)
h' = Mirror(h, ω)
g' = Mirror(g, ω)
S_3 = Center(h')
S_4 = Center(g')