def Hadamard(k):
	H = Matrix(1,1)
	H[0,0] = 1
	for i in range(k):
		m = 2**i
		newH = Matrix(2*m, 2*m)
		newH[:m, :m] = H
		newH[:m, m:] = H
		newH[m:, :m] = H
		newH[m:, m:] = -H
		H = newH
	return H