x_1, x_2, x_3, 
-2*x_1*x_3^3-2*x_1^2*x_3+2*x_1*x_2*x_3+x_2*x_3^2+x_1*x_2-x_2^2
x_1^2*x_3^2-2*x_1*x_3^3+x_3^4+x_1^3-x_1^2*x_2-2*x_1^2*x_3+2*x_1*x_2*x_3+x_1*x_3^2-x_2*x_3^2
