source 2008 Sutherland
compute U = 2 Y1
compute V = U^2
compute W = U V
compute S = X1 V
compute M = 3 X1^2+a ZZ1^2
compute X3 = M^2-2 S
compute Y3 = M (S-X3)-W Y1
compute ZZ3 = V ZZ1
compute ZZZ3 = W ZZZ1
