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