A = (-5, 0)
B = (-2, -1)
C = (-3, 3)
veelhoek1, c, a, b = Polygon(A, B, C)
veelhoek2, d, e, f, g, D, E = Polygon(A, C, 4)
veelhoek3, h, i, j, k, F, G = Polygon(B, A, 4)
veelhoek4, l, m, n, p, H, I = Polygon(C, B, 4)
α = Angle(B, A, C)
β = Angle(A, C, B)
γ = Angle(C, B, A)