A = XX1^2 B = ZZ1^2 C = A+B t0 = XX1+ZZ1 t1 = t0^2 t2 = t1-C D = 2*t2 E = A-B F = 2*A G = 2*B t3 = 2*C t4 = a*D J = t4+t3 K = J+E L = J-E M = C*E N = G*K P = F*L t5 = M-N X3 = X1*t5 t6 = D*E t7 = M+N t8 = P-M t9 = t6^2 t10 = t7*t8 t11 = t10+t9 Y3 = Y1*t11 t12 = P+M Z3 = Z1*t12 XX3 = X3^2 ZZ3 = Z3^2 t13 = X3+Z3 t14 = t13^2 t15 = t14-XX3 R3 = t15-ZZ3