  We demonstrate that the spectacular structures discovered recently in various
experiments and named as $X$, $Y$ and $Z$ states cannot be purely kinematic
effects. Their existence necessarily calls for nearby poles in the $S$--matrix
and they therefore qualify as states. We propose a way to distinguishing
kinematic cusp effects from genuine $S$--matrix poles: the kinematic threshold
cusp cannot produce a narrow peak in the invariant mass distribution in the
elastic channel in contrast with a genuine $S$--matrix pole.
