Author: IREM de Paris-Nord

A = (0, -3)
B = (6, -3)
C = (6, 3)
D = (0, 3)
E = (2, 3)
F = (4, 3)
G = (0, 1)
H = (0, -1)
I = (2, -3)
J = (4, -3)
K = (6, -1)
L = (6, 1)
a = Segment(D, C)
b = Segment(C, B)
c = Segment(B, A)
d = Segment(A, D)