S = (7.44, 1.26)
B = (2.3, 2.82)
k_{4} = Circle(S, B)
C = (6.24, 1.86)
k_1 = Circle(S, C)
T = Point(k_{4})
p = Tangent(T, k_{4})
f = OrthogonalLine(T, p)
A, D = Intersect(k_1, f)
S_3 = Midpoint(A, T)
S_4 = Midpoint(D, T)
k_3 = Circle(S_3, A)
k_2 = Circle(S_4, D)
a = 0 (slider from 0 to 4, step 1)