A = X1*X2 B = Y1*Y2 C = T2 D = T1 E = D+C t0 = X1-Y1 t1 = X2+Y2 t2 = t0*t1 t3 = t2+B F = t3-A t4 = a*A G = B+t4 H = D-C X3 = E*F Y3 = G*H T3 = E*H Z3 = F*G