$z_1$

$z_2$

$z_3$

$\gamma_{1}^{(0)}$

$\gamma_{3}^{(0)}$

$\gamma_{2}^{(0)}$

Im

Re

Z_1 = (1, 1)
Z_2 = (6, 2)
Z_3: (3, 6)
v_{1,n} = Vector(Z_1, Z_2)
v_{3,n} = Vector(Z_3, Z_1)
v_{2,n} = Vector(Z_2, Z_3)