c = Circle((0, 0), 1)
O = Center(c)
A = Point(c)
f = Line(O, A)
B = Intersect(c, f, 2)
M = Point(c)
t1, b, a, c_1 = Polygon(A, M, B)
g = Segment(M, O)
α = Angle(M, O, A)
β = Angle(O, A, M)
γ = Angle(A, M, O)
δ = Angle(O, M, B)
ε = Angle(M, B, O)
ζ = Angle(B, O, M)
N = Mirror(M, O)