I-band light curves (left) of 4 periodic variables flagged as “short”, “short with extra variability”, “long”, and “long with extra variability”, respectively. These are folded to their derived periods (right). In this sample, the folded light curves of SMC5_004201 and 2dFS5020, which exhibit extra variability, correspond to the HJD ranges 2 454 000−2 455 000 and 2 454 200−2 455 000, respectively.