w1 = [1, 2, 0]
w2 = [0, 2, 1]
w3 = [2, 0, -1]
w4 = [1, -2, 0]
v1 = w1 = [1, 2, 0]
v2 = w2 - (v1·w2)/(v1·v1)·v1
v2 = [0, 2, 1] - [1, 2, 0]·[0, 2, 1]/([1, 2, 0]·[1, 2, 0])·[1, 2, 0] = [-0.8, 0.4, 1]
v3 = w3 - (v1·w3)/(v1·v1)·v1 - (v2·w3)/(v2·v2)·v2
v3 = [2, 0, -1] - ([1, 2, 0]·[2, 0, -1])/([1, 2, 0]·[1, 2, 0])·[1, 2, 0] - ([-0.8, 0.4, 1]·[2, 0, -1])/([-0.8, 0.4, 1]·[-0.8, 0.4, 1])·[-0.8, 0.4, 1] = [4/9, - 2/9, 4/9]
v4 = w4 - (v1·w4)/(v1·v1)·v1 - (v2·w4)/(v2·v2)·v2 - (v3·w4)/(v3·v3)·v3
v4 = ...