repeated(X) --> [X], repeated(X), [_].
repeated(_) --> [].

reversePlural([H|T]) -->
    phrase(repeated(H), T),
    reversePlural(T),
    [_].
reversePlural([]) --> [].

% Want to match:
% phrase(reversePlural([a,b,c]), [a,a,a,b,b,b,c,c,c]).