  The emergence of interference is observed in the resistance of a graphene
annulus pn junction device as a result of applying two separate gate voltages.
The observed resistance patterns are carefully inspected, and it is determined
that the position of the peaks resulting from those patterns are independent of
temperature and magnetic field. Furthermore, these patterns are not
attributable to Aharonov-Bohm oscillations, Fabry Perot interference at the
junction, or moir\'e potentials. The device data are compared with those of
another device fabricated with a traditional Hall bar geometry, as well as with
quantum transport simulation data. Since the two devices are of different
topological classes, the subtle differences observed in the corresponding
measured data indicate that the most likely source of the observed geometric
interference patterns is quantum scarring.
