A = X1*X2 B = Y1*Y2 t0 = d*T2 C = T1*t0 t1 = X1+Y1 t2 = X2+Y2 t3 = t1*t2 t4 = t3-A E = t4-B F = 1-C G = 1+C t5 = a*A H = B-t5 X3 = E*F Y3 = G*H T3 = E*H t6 = C^2 Z3 = 1-t6