A = Corner(pic1, 1)
B = Corner(pic1, 2)
C = Corner(pic1, 3)
D = Corner(pic1, 4)
h: z(e)
a = Segment(D, C)
b = Segment(A, B)
E = Intersect(a, e)
F = Intersect(b, e)
G = Point(a)
H = Point(b)
poly1, g, e_1, f, h_1 = Polygon(G, E, F, H)
I = Point(b)
poly2, e_2, c, b_1, f_1 = Polygon(E, C, B, F)
H' = Mirror(H, e)
J: H' - (B - H)
G' = Mirror(G, e)
poly3, h', b_2, c_1, g' = Polygon(H', B, C, G')