+

O = (-0.64, 1.76)
B = (2.36, 1.76)
a = Ray(O, B)
C = (1.38, 3.96)
A = (1.64, 2.16)
D = (1.14, 3.24)
c = CircleArc(O, A, D)
E = Point(c)
u = Vector(E, D)
F = (3.26, 2.32)
G = (2.98, 3.14)
H = (2.6, 3.9)
α = 0.8552113334772214 rad (slider from 0 to 6.283185307179586, step 0.017453292519943295)
I = Point(a)
I' = Rotate(I, α, O)
β = Angle(I, O, I')
b = Ray(O, I')