Q[a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,u]
{
o*q+m*r,n*q+l*r,i*q+g*r,h*q+f*r,m*n-l*o,i*m-g*o,h*m-f*o,i*l-g*n,h*l-f*n,g*h-f*i
}