domains
  sylist=symbol*
predicates
  palin(sylist)
  reverse(sylist,sylist)
  append(sylist,sylist,sylist)
clauses
  palin([]).
  palin([X|[Y,X]]).
  palin([X|L]):-
    reverse(L,[X|M]),palin(M).
  
  reverse([],[]).
  reverse([Head|Tail],Result):-
    !,
    reverse(Tail,Temp),
    append(Temp,[Head],Result).
  append([],List,List).
  append([Head|List1],List2,[Head|Rest]):-
     append(List1,List2,Rest),!.