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