w1  =  [ 0.2 -1.3  0.34  -1.1]
w2  =  [ 0.5 -0.6  0.7    0.8]
w3  =  [-1.0  1.0  2.0    4.5]  
w4  =  [-5.1  0.0  1.6   -1.7]

v   =  [ 1.7  2.3  1.0   -5.0] 
