D' = (7.11544,2.89808)

A': (1.16611, 1.18031)
B': (4.82413, 2.2365)
f = Line(A', B')
C' = Point(f)
g = Line(A', C')
A = (4.761331503806084, 4.130601813754447)
h = Line(A', A)
i = Line(B', A)
j = Line(A, C')
B = Point(h)
k = Line(C', B)
C = Intersect(i, k)
l = Line(A', C)
D = Intersect(j, l)
m = Line(B, D)
E = Intersect(g, m)
n = Line(C, E)
F = Intersect(n, j)
p = Line(F, B)
G = Intersect(g, p)
q = Line(C, G)
H = Intersect(q, j)
r = Line(B, H)
D' = Intersect(g, r)
a = CrossRatio(A', C', D', B')