source 2008 Bernstein--Lange--Rezaeian Farashahi appliesto wz-1 assume Z1 = 1 compute C = W2(Z2+W2) compute D = W3(Z3+W3) compute E = Z2 Z3 compute V = C D compute U = V + d1 E^2 compute W5 = V + W1 U compute Z5 = U