  We study a population of swarmalators (swarming/mobile oscillators) which run
on a ring and are subject to random pinning. The pinning represents the
tendency of particles to stick to defects in the underlying medium which
competes with the tendency to sync / swarm. The result is rich collective
behavior. A highlight is low dimensional chaos which in systems of ordinary,
Kuramoto-type oscillators is uncommon. Some of the states (the phase wave and
split phase wave) resemble those seen in systems of Janus matchsticks or
Japanese tree frogs. The others (such as the sync and unsteady states) may be
observable in systems of vinegar eels, electrorotated Quincke rollers, or other
swarmalators moving in disordered environments.
