A = (-0.72, 1)
B = (3.3125018573444294, 0.5651987214559231)
O = (2.3, 1.76)
A' = Mirror(A, O)
B' = Mirror(B, O)
f = Segment(A, O)
g = Segment(O, A')
h = Segment(B', O)
i = Segment(O, B)
j = Line(B', A')
k = Line(A, B)
etape = 3 (slider from 0 to 3, step 1)
α = Angle(A', O, B')
β = Angle(A, O, B)
l = Segment(B', A')
m = Segment(A, B)
γ = Angle(B', A', O)
δ = Angle(B, A, O)
ε = Angle(O, B, A)
ζ = Angle(O, B', A')