Le théorème de Pappus :
D,E,F sont alignés

O = (0.38, -0.1)
A = (4.18, 2.04)
a = Line(A, O)
B' = (6.56, -1.58)
b = Line(O, B')
B = Point(a)
C = Point(a)
A' = Point(b)
C' = Point(b)
c = Line(A, B')
d = Line(A', B)
e = Line(A, C')
f = Line(A', C)
g = Line(C', B)
h = Line(C, B')
F = Intersect(c, d)
E = Intersect(e, f)
D = Intersect(g, h)
i = Line(F, D)