a = 0 (slider from -5 to 5, step 0.05)
b: x = a
A = (1, 2)
B = Point(xAxis)
C = (3, 4)
poly1, c, a_1, b_1 = Polygon(A, B, C)
A' = Mirror(A, b)
B' = Mirror(B, b)
C' = Mirror(C, b)
poly1', c', a', b' = Polygon(A', B', C')