A: (0, 0)
B: (21, 0)
C: (0, 29.7)
D: (21, 29.7)
E: (1, 1)
F: (20, 1)
G: (1, 28.7)
H: (20, 28.7)
q1, a_1, b, d, c = Polygon(A, B, D, C)
q2, e, f, h, g = Polygon(E, F, H, G)
a = 9 (slider from 0 to 18, step 0.1)
I: (1 + a, 28.7)
J: (1, 28.7 - a)
K: (1 + a, 28.7 - a)
q3, g_1, i, k, j = Polygon(G, I, K, J)
L: (2 + a, 28.7)
M: (2 + a, 28.7 - a)
N: (20, 28.7 - a)
q4, l, h_1, n, m = Polygon(L, H, N, M)
texte1: "x=" + a + "
S(a)=" + ((a * (18 - a))) + ""
p = Segment(G, K)
q = Segment(I, J)