#hide rotate/3.
#hide color/4.

 :- chosenTile(X,Y,N), not row(Y).
 :- chosenTile(X,Y,N), not col(X).
 :- chosenTile(X,Y,N), not tile(N).
 :- chosenRotation(X,Y,R), not row(Y).
 :- chosenRotation(X,Y,R), not col(X).
 :- chosenRotation(X,Y,R), not rotation(R).

rotate(R,0,R) :- rotation(R).
rotate(top,90,right).    rotate(top,180,bottom). rotate(top,270,left).
rotate(right,90,bottom). rotate(right,180,left). rotate(right,270,top).
rotate(bottom,90,left).  rotate(bottom,180,top). rotate(bottom,270,right).
rotate(left,90,top).     rotate(left,180,right). rotate(left,270,bottom).

 :- not 1 { chosenTile(X,Y,N) : row(Y) : col(X) } 1, tile(N).
 :- not 1 { chosenTile(X,Y,N) : tile(N) } 1, row(Y), col(X).
 :- not 1 { chosenRotation(X,Y,R) : rotation(R) } 1, row(Y), col(X).

color(X,Y,SR,C) :- chosenTile(X,Y,N), chosenRotation(X,Y,R), tileSide(N,S,C), rotate(S,R,SR).

 :- color(X,Y,right,C1), color(X+1,Y,left,C2), C1 != C2.
 :- color(X,Y,bottom,C1), color(X,Y+1,top,C2), C1 != C2.