% | 1 | 2 | 3 |
% | 4 | 5 | 6 |
% | 7 | 8 | 9 |

rook(1,2).
rook(1,4).
rook(2,3).
rook(2,5).
rook(3,6).
rook(4,5).
rook(4,7).
rook(5,6).
rook(5,8).
rook(6,9).
rook(7,8).
rook(8,9).

rookbi(X,Y):-rook(X,Y);
             rook(Y,X).

move_user(X,Y) :- retractall(visited(Z)),
	          asserta(visited(X)),
	          asserta(visited(Y)),
	          move(X,Y).

move(X,Y) :- rookbi(X,Y).
move(X,Y) :- rookbi(X,Z),
	     not(visited(Z)),
	     asserta(visited(Z)),
	     print(Z),nl,
	     move(Z,Y).