3%p(X, Y, Z):- all_pos(X, Y), all_pos(Y, Z).
    4
    5% When the above works, try the one below
    6p(X, Y, Z):- all_pos(X, Y), all_pos(Y, Z), all_pos(X, Z).
    7
    8all_pos(A, B):- A .>. B.
    9all_pos(A, B):- A .=<. B.
   10
   11q:- not p(X, Y, Z).
   12
   13
   14?-  not q. %% Should succeed