A = (-1, 0)
B = (3, 1)
C = (6, 4)
a = Segment(A, B)
b = Segment(B, C)
c = Line(C, a)
d = Line(A, b)
D = Intersect(c, d)
poli1, a_1, b_1, c_1, d_1 = Polygon(A, B, C, D)