allgemein:
y_o - f(x_o - d) = f(x_o + d) - y_o

Koordinaten von Z:

Abstand  d zwischen x_o
und den untersuchten Stellen:

y_o = 0 (slider from -3 to 3, step 0.1)
x_o = 0 (slider from -5 to 5, step 0.1)
d = 2.5 (slider from -5 to 15, step 0.1)
P1: (x_o + d, y_o)
f(x) = 2 * (x - x_o) / ((x - x_o)^(2) - 4) + y_o
Q1: (x_o + d, f(x_o + d))
P2: (x_o - d, y_o)
Q2: (x_o - d, f(x_o - d))
Z: (x_o, y_o)
poly1, d1, o, p1 = Polygon(Z, P1, Q1)
poly2, d2, o_1, p2 = Polygon(Z, P2, Q2)
yd: y_o - f(x_o - d)
T3: y_o + " - f(" + x_o + " - " + d + ") = " + yd + " = f(" + x_o + " + " + d + ") -" + y_o
T1: "Kurve mit Punktsymmetrie zu Z(" + x_o + " | " + y_o + ")"
T2: "f(x)= 2(x-" + x_o + ") / ((x-" + x_o + ")² - 4)"
Y1: (0, f(x_o + d))
YZ: (0, y_o)
Y2: (0, f(x_o - d))
b = Segment(Y1, Q1)
c = Segment(YZ, Z)
e = Segment(Y2, Q2)
g = Segment(YZ, Y1)
h = Segment(YZ, Y2)
dy: y_o - f(x_o - d)