T1 = X1^2
T2 = Z1^2
T3 = a*T2
T4 = T1-T3
T5 = T4^2
T6 = b*T2
T7 = X1*Z1
T8 = T6*T7
T9 = 8*T8
X3 = T5-T9
T10 = T1+T3
T11 = T7*T10
T12 = T6*T2
T13 = T11+T12
Z3 = 4*T13