Angles
Author: m@ths et tiques 2012

A = (1.6844103104593147, 0.9818640731917616)
B = (-1.2369838794821355, 1.3876132662391851)
a = Line(A, B)
C = (0.8931993840168385, -1.0265944323929852)
b = Line(A, C)
D = Point(b)
E = (-1.4792032871012275, 3.385540697050764)
c = Line(D, E)
α = Angle(c, b)
F = Point(b)
G = Point(c)
β = Angle(G, D, F)
H = Point(a)
γ = Angle(H, A, F)