id = 141
group = 'trees'
number = 46
visible = True
facts = None

solution = '''\
conc141([], L, L).
conc141([H|T], L2, [H|L]) :-
  conc141(T, L2, L).

tolistBT(nil, []).
tolistBT(b(L, E, R), List) :-
  tolistBT(L, LL),
  tolistBT(R, RL),
  conc141(LL, [E|RL], List).
'''