source 2008 Bernstein--Lange--Rezaeian Farashahi appliesto wz-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 Z1 + U W1 compute Z5 = U Z1