A = (11.12, -5.2)
B = (19.12, -5.7)
f = Line(A, B)
g = OrthogonalLine(A, f)
h = OrthogonalLine(B, f)
S_1 = Point(g)
k_1 = Circle(S_1, A)
S_2 = Point(h)
k_2 = Circle(S_2, B)
C = Intersect(k_1, g, 2)
i = OrthogonalLine(C, g)
D = Intersect(k_2, h, 2)
j = OrthogonalLine(D, h)
k = Line(B, C)
l = Line(A, D)
E = Intersect(k_1, k, 2)
F = Intersect(k_2, l, 2)
m = LineBisector(E, B)
n = LineBisector(F, A)
S_3 = Intersect(h, m)
S_4 = Intersect(g, n)
k_3 = Circle(S_3, B)
k_4 = Circle(S_4, A)
a = 0 (slider from 0 to 6, step 1)