 \frac{ \pi }{2 } 

 \frac{ 3\pi }{2 } 

\pi

-\pi

- \frac{ \pi }{2 } 

- \frac{ 3\pi }{2 } 

 \frac{ 5\pi }{2 } 

O = (-1, 0)
I = (0, 0)
c = Circle(O, I)
M = Point(yAxis)
N = Rotate(I, y(M), O)
α = Angle(I, O, N)
d = CircleArc(O, I, N)
a = Segment(N, O)
b = Segment(O, I)
B = Midpoint(N, M)
e = LineBisector(N, M)
C = Intersect(e, f)
h = CircleArc(C, N, M)
k = CircleArc(O, N, I)
g = CircleArc(C, M, N)
β = Angle(N, O, I)
i = Segment(I, M)
I2 = (-1, 1)
I3 = (-2, 0)
I4 = (-1, -1)
O1 = (-1, 0)
text1: "IM=" + (y(M)) + ""
text2: "\widehat{ION}=" + (LaTeX[Mod[y(M), 6.283185307179586]]) + "\\
\widehat{ION}=" + (LaTeX[Mod[y(M), 6.283185307179586] / π]) + "\pi"