A = (1, 1)
c = Circle(A, 1)
C = Point(c)
B = Point(c)
f = Segment(B, A)
g = Segment(A, C)
AB = Segment(C, B)
D = Point(c)
a = CircumcircleArc(C, D, B)
E = Point(c)
r = Segment(A, E)