x1 = -0.90 +0.44i
x2 = -0.90 -0.44i
x3 = -0.20 +0.96i
x4 = -0.20 -0.96i
x5 =  0.62 +0.74i
x6 =  0.62 -0.74i
x7 =  0.95 +0.00i