x1, x2, x3, x4, x5, x6, x7, x8, x9, u1, u2, u3, u4, 
u1*x2-u1*x9-u2*x1+u2*x9+x1*x8-x2*x8
x4*x7-x4*x9-x5*x6+x5*x8+x6*x9-x7*x8
-x4*x6+x4*x8-x5*x7+x5*x9
u3*x7+u4*x3-u4*x7-x3*x6
u2*x5+u4*x2-u4*x5-x2*x4
u1*x3-u1*x5-u3*x1+u3*x5+x1*x4-x3*x4
u3^2-u4^2+x3^2
u2^2-u4^2+x2^2
u1^2-u4^2+x1^2
