A = (2.88, -8.18)
B = (8.42, -1.86)
p_1 = Line(A, B)
C = (21.32, -9.86)
p_2 = Line(A, C)
D = Point(p_1)
h = OrthogonalLine(D, p_1)
S = Point(h)
k = Circle(S, D)
f = OrthogonalLine(D, p_1)
g, i = AngularBisector(p_1, p_2)
S_1 = Intersect(f, i)
k_1 = Circle(S_1, D)
S_2 = Intersect(f, g)
k_2 = Circle(S_2, D)
G = Mirror(S, p_1)
j = OrthogonalLine(G, f)
k_{5} = Parabola(S, j)
S_3, S_4 = Intersect(k_{5}, g)
l = Line(S_3, S)
m = Line(S_4, S)
J = Intersect(k, l, 1)
k_3 = Circle(S_3, J)
K = Intersect(k, m, 1)
k_4 = Circle(S_4, K)
a = 0 (slider from 0 to 6, step 1)