f(x) = exp(x)
P = Point(f)
t = Tangent(P, f(x))
n = OrthogonalLine(P, t)
B = Intersect(n, yAxis)
C = Intersect(t, yAxis)
Vieleck1, c, b_1, a_1 = Polygon(B, P, C)
D: (x(P), Vieleck1)
D' = Mirror(D, yAxis)