E: (1, 9)
F: (3, 9)
G: (1, 6)
u = Vector(E, F)
v = Vector(E, G)
A = (5, 7)
B = (6, 6)
C = (5, 4)
D = (4, 6)
cerfvolant1, a, b, c, d = Polygon(A, B, C, D)