  The observation of many unexpected states decaying into heavy quarkonia has
challenged the usual Q-Qbar interpretation. We will discuss the nature of some
of the charmonium-like resonances recently observed by BES III and LHCb, and
their identication according to the compact tetraquark model. We also commment
the production of light nuclei in hadron collisions and the relevance for the
physics of the X(3872).
