The subspace W is equal to span{a,b,c,d}, where:
a = [1, 1, 1, 1], b = [0, -1, -1, -1], c = [0, 0, 1, -1]
To produce an orthonormal basis for W using the Gram Schmidt method, you do the following:
1. Take one of the vectors, say a, and divide by its norm to get q1. q1 = a/|a|
2...