  Pentaquark baryons are a natural expectation of an extended picture of
hadrons where quarks and diquarks are the fundamental units. The parity/mass
pattern observed, when compared to that of exotic mesons, appears as the
footprint of a compact five-quark structure. What has been learned from the
X,Y,Z phenomenology informs about the newly found pentaquark structure and
suggests further experimental tests and directions to be explored.
