O = Intersect(yAxis, xAxis)
a = 1
c = Circle(O, a)
A, B = Intersect(c, xAxis)
w = 0 (slider from 0 to 360, step 1)
P = Rotate(B, w °, O)
α = Angle(B, O, P)
h = Ray(O, P)
S: (w 3.1416 / 180, y(P))
C: (w 3.1416 / 180, x(P))
b = CircleArc(O, B, P)
e = OrthogonalLine(S, xAxis)
D = Intersect(e, xAxis)
b' = Segment(O, D)