задача на перестановку кубиков методом поиска в ширину

domains
    s=symbol
    list=s*
    l2=list*
    l3=l2*
    l4=l3*
predicates
 
nondeterm   tgoal(l2)
nondeterm   delete(list,l2,l2)
nondeterm   member(l2,l3)
nondeterm   conc(l4,l4,l4)
nondeterm   after(l2,l2)
nondeterm   solve(l2,l3)    
nondeterm   in_width(l4,l3)
nondeterm   new_node(l2,l3,l3)
nondeterm   write_list(l3)  
clauses
    tgoal([[a,b,c],[],[]]). tgoal([[],[a,b,c],[]]). tgoal([[],[],[a,b,c]]). 
    after(Stolbs,[Stolb1,[Up1|Stolb2]|Rest]):-
        delete([Up1|Stolb1],Stolbs,Stolbs1), delete(Stolb2,Stolbs1,Rest).
    delete(X,[X|L],L).
    delete(X,[Y|L],[Y|L1]) :- delete(X,L,L1).
    member(X,[X|_]).
    member(X,[_|Tail]):- member(X,Tail).
    conc([],L,L).
    conc([X|L1],L2,[X|L3]) :- conc(L1,L2,L3).
solve(Start,Solution) :- in_width([[Start]],Solution).
in_width([[Node|Path]|_],[Node|Path]) :- tgoal(Node).
in_width([[B|Path]|Paths],Solution) :- findall(S, new_node(B,S,Path),   NewPaths),
        /* NewPaths - ациклические продолжения пути [B|Path] */
    conc(Paths,NewPaths,Paths1),!, in_width(Paths1,Solution);
        in_width(Paths,Solution).  % случай, когда у B нет преемника
new_node(B,S,Path) :- after(B,B1), not(member(B1,[B|Path])), S=[B1,B|Path].
write_list([X|Rest]):-write("\n",X),readchar(_), write_list(Rest).
write_list([]).             
goal
    solve([[c,a,b],[],[]],Solution), write_list(Solution).

domains
    list=char*
    l2=list*
    l3=l2*
    l4=l3*
database
tgoal(l2)   
predicates
    
nondeterm   delete(list,l2,l2)
determ  member(l2,l3)
determ  conc(l4,l4,l4)
nondeterm   after(l2,l2)
nondeterm   solve(list,l3)  
determ  in_width(l4,l3)
nondeterm   new_node(l2,l3,l3)
determ  write_list(l3)  
convert (string,list)
 
clauses
  convert(S1,[H|T]):- frontchar(S1,H,S2),!,convert(S2,T).
convert(_,[]).
        
    after(Stolbs,[Stolb1,[Up1|Stolb2]|Rest]):-
        delete([Up1|Stolb1],Stolbs,Stolbs1), delete(Stolb2,Stolbs1,Rest).
    delete(X,[X|L],L).
    delete(X,[Y|L],[Y|L1]) :- delete(X,L,L1).
    member(X,[X|_]).
    member(X,[_|Tail]):- member(X,Tail).
    conc([],L,L).
    conc([X|L1],L2,[X|L3]) :- conc(L1,L2,L3).
    
solve(Start,Solution) :-in_width([[Start]],Solution).
in_width([[Node|Path]|_],[Node|Path]) :- tgoal(Node).
in_width([[B|Path]|Paths],Solution) :- findall(S, new_node(B,S,Path),   NewPaths),
        
    conc(Paths,NewPaths,Paths1),!, in_width(Paths1,Solution);
        in_width(Paths,Solution). 
new_node(B,S,Path) :- after(B,B1), not(member(B1,[B|Path])), S=[B1,B|Path].
write_list([X|Rest]):-write("\n",X),readchar(_), write_list(Rest).
write_list([]).             
goal
write("Vvedite nachalnoe znachenie\n"),
readln(Str),convert(Str,Start), 
assert(tgoal([Start,[],[]])),
write("Vvedite konechnoe znachenie\n"),readln(Str2),
convert(Str2,Endl),
solve( Endl,Solution),write_list(Solution),nl.