A = Z1^2 B = Z2^2 t0 = Z1+Z2 t1 = t0^2 t2 = t1-A C = t2-B D = X1*Z2 E = X2*Z1 F = Y1*B G = Y2*A H = D-E t3 = F-G I = 2*t3 II = I^2 J = C*H t4 = J*H K = 4*t4 t5 = D+E t6 = t5*K t7 = 2*II X3 = t7-t6 JJ = J^2 t8 = J+I t9 = t8^2 t10 = D*K t11 = t9-JJ t12 = t11-II t13 = t10-X3 t14 = K^2 t15 = F*t14 t16 = t12*t13 Y3 = t16-t15 Z3 = 2*JJ