B = XX1-ZZ1 T1 = XX1+ZZ1 C = Y1*T1 t0 = X1+Z1 t1 = t0^2 t2 = Y1*t1 X3 = C-t2 Z3 = T1*B XX3 = X3^2 ZZ3 = Z3^2 T3 = XX3+ZZ3 t3 = C^2 t4 = 2*t3 Y3 = t4-T3