x_1, x_2, x_3, 
2*x_1*(x_1^4+2*x_1^2*x_2^2+2*x_1^2*x_3^2-x_2^4-x_3^4)
-2*x_2*(x_1^4-2*x_1^2*x_2^2-x_2^4-2*x_2^2*x_3^2+x_3^4)
-2*x_3*(x_1^4-2*x_1^2*x_3^2+x_2^4-2*x_2^2*x_3^2-x_3^4)
