A = (-3, 3)
B = (-1, 1)
C = (3, 1)
a = Segment(B, C)
d = Line(A, B)
b = OrthogonalLine(B, a)
d' = Mirror(d, b)
c = Line(A, C)
e = OrthogonalLine(C, a)
c' = Mirror(c, e)
D = Point(c')
E = Point(d')
poly1, b_1, c_1, d_1, e_1 = Polygon(B, C, D, E)