A = X1
B = Y1
C = Z1*X2
D = Z1*Y2
E = A*B
F = C*D
G = E+F
H = E-F
t0 = A+D
t1 = B+C
t2 = t0*t1
t3 = t2-G
X3 = t3*H
t4 = A-C
t5 = B+D
t6 = t4*t5
t7 = t6-H
Y3 = t7*G
t8 = G*H
Z3 = c*t8