  The so-called "dipper" stars host circumstellar disks and have optical and
infrared light curves that exhibit quasi-periodic or aperiodic dimming events
consistent with extinction by transiting dusty structures orbiting in the inner
disk. Most of the proposed mechanisms explaining the dips---i.e., occulting
disk warps, vortices, and forming planetesimals---assume nearly edge-on viewing
geometries. However, our analysis of the three known dippers with publicly
available resolved sub-mm data reveals disks with a range of inclinations, most
notably the face-on transition disk J1604-2130 (EPIC 204638512). This suggests
that nearly edge-on viewing geometries are not a defining characteristic of the
dippers and that additional models should be explored. If confirmed by further
observations of more dippers, this would point to inner disk processes that
regularly produce dusty structures far above the outer disk midplane in regions
relevant to planet formation.
