AxB = {(a,1), (a,2), (b,1), (b,2), (c,1), (c,2), (d,1), (d,2)}
BxA = {(1,a), (1,b), (1,c), (1,d), (2,a), (2,b), (2,c), (2,d)}
AxB = {(a,1), (a,2), (b,1), (b,2), (c,1), (c,2), (d,1), (d,2)}
BxA = {(1,a), (1,b), (1,c), (1,d), (2,a), (2,b), (2,c), (2,d)}