A = Point(yAxis)
B = Point(Circle[A, 6.28])
f = Segment(A, B)
C = Point(f)
c = Circle(C, 1)
D = Point(c)
a: x(C)
D' = Rotate(D, (-a), C)
E = Intersect(xAxis, yAxis)
g = Segment(E, D)
d = CircleArc(C, D, D')