import numpy as np

b1 = np.array([[-2, 1, 0],
                [1, 0, 2],
                [-1, 1, 0]])

b2 = np.array([[1, 0, 1],
               [0, 1, 2],
               [-1, -1, 0]])

vb1 = np.array([2, 1, 1])

def coordinates(vector, basis):
   np.