voir A'B'C'

A_1 = (6, 5)
B_1 = (1, 0)
f = Line(A_1, B_1)
A = (0, 5)
B = (3, 6)
C = (1, 2)
t1, e, c, d = Polygon(A, B, C)
A' = Mirror(A, f)
B' = Mirror(B, f)
C' = Mirror(C, f)
t1', c', a', b' = Polygon(A', B', C')
a = false