R = Y1+Z1 S = Y1-Z1 T = R^2 U = S^2 t0 = 3*U V = T+t0 t1 = 3*T W = t1+U C = R*V D = S*W t2 = W-V t3 = X1*t2 t4 = d*t3 t5 = 3*C E = t5-t4 t6 = X1*D X3 = minustwo*t6 t7 = D+E Y3 = t7*Z1 t8 = D-E Z3 = t8*Y1