:- use_module(library(lists)).
:- use_module(library(time)).

% Is the new unification really fast?


test(2^N-T) :-
	length(_,N),
	N > 17,
	BN is 2^N,
	length(L, BN),
	time(t(L)).

t(L) :-
	unify_with_occurs_check(L,V),
	V \= [].