x_1, x_2, x_3, x_4, x_5, x_6, x_7, 
2*x_1*x_7+2*x_2*x_6+2*x_3*x_5+2*x_4*x_6-x_3
2*x_1*x_6+2*x_2*x_5+2*x_3*x_6+2*x_4*x_7+x_7^2-x_2
2*x_1*x_4+2*x_1*x_5+2*x_2*x_6+2*x_3*x_7+2*x_6*x_7-x_1
2*x_1*x_3+2*x_1*x_6+2*x_2*x_4+2*x_2*x_7+2*x_5*x_7+x_6^2-x_7
2*x_1*x_2+2*x_1*x_7+2*x_2*x_3+2*x_3*x_4+2*x_5*x_6+2*x_6*x_7-x_6
x_5+2*x_6+2*x_7+2*x_1+2*x_2+2*x_3+2*x_4-1
2*x_1^2+2*x_2^2+2*x_3^2+2*x_4^2+x_5^2+2*x_6^2+2*x_7^2-x_5
