stap = 30 (slider from 0 to 30, step 1)
B': (10.1, -0.13)
C: (6, -3)
g = Line(B', C)
D = Point(g)
A': (2.17, 0.21)
h = Line(A', C)
E = Point(h)
i = Segment(D, B')
ζ = Angle(D, C, E)
η = Angle(B', C, E)
j = Segment(E, A')
ε = Angle(A', C, D)
δ = Angle(B', C, A')
F = (0.8094227488204797, -6.628472412646038)