r = 1.7 (slider from 0.2 to 5, step 0.1)
O_1 = (-2.828712847414411, 4.178727207330659)
O = (-2.3994368304859592, 4.1171181493455515)
c = Circle(O, r)
A = (-5.340772502032763, 5.249929860684523)
B = Point(c)
C = Point(c)
a = Segment(A, C)
b = Segment(A, B)
D = Intersect(c, a, 2)
d = Segment(D, B)
α = Angle(C, A, B)
β = Angle(C, D, B)
γ = Angle(A, B, D)
e = CircleArc(O, C, B)
E = Intersect(c, b, 2)
f = CircleArc(O, E, D)