φ = 0 rad (slider from 0 to 3.141592653589793, step 0.008726646259971648)
v: (3.0 * cos(φ) - 2.0, 3.0)
A = (2, 1)
B_n = Translate(A, v)
u = Vector(A, B_n)
w: (2.0 * cos(φ) - 3.0, sin(φ) * sin(φ))
C_n = Translate(A, w)
z = Vector(A, C_n)
Vieleck1, b_n, a, c_n = Polygon(A, C_n, B_n)
α = Angle(B_n, A, C_n)