Il segmento rimane costante 
durante la trasformazione.

g = 0 (slider from 0 to 2, step 0.01)
B = (1, -1)
A = (-3, -1)
a = Line(A, B)
D = (-3, 3)
poly1, d, a_1, b_1 = Polygon(A, B, D)
E = (-4, 2)
c = Line(E, a)
F = Intersect(c, b_1)
G = Intersect(c, a_1)
e = Segment(F, G)
H: D + (B - A) * g
poly2, h, a_2, b_2 = Polygon(A, B, H)
I = Intersect(c, b_2)
J = Intersect(c, a_2)
f = Segment(I, J)
H': H + B - A
poly3, h_1, b_3, h' = Polygon(B, H', H)
K = Intersect(c, h_1)
i = Segment(J, K)
b = Line(D, a)