C = X1*X2 D = Y1*Y2 E = C*D H = C-D t0 = X1+Y1 t1 = X2+Y2 t2 = t0*t1 t3 = t2-C I = t3-D t4 = E+d t5 = t4*H X3 = c*t5 t6 = E-d t7 = t6*I Y3 = c*t7 Z3 = H*I