?- delete(a,[a,c,[a,b],a,f],R).
           	R=[c,[a,b],f]
 

           	delete(X,[],[]).
           	delete(X,[X|T],R):- delete(X,T,R),!.
           	delete(X,[Y|T],[Y|R]):- delete(X,T,R).

		Deletes all the elements from another list        
        	?- delete2([1,2,3],[1,4,2,5,3,7],R).
        	R=[4,5,7]          
 
        	delete2([],L1,L1).
        	delete2([H|T],L1,L3):-delete2(H,L1,R2),delete2(T,R2,L3).