The word “ephemera” comes from the Greek ephemeros, referring to forms that are fleeting by nature. And thus Ephemera is an apt name for an exhibit, at Future Tenant, exploring permanence and transience. The ongoing exhibit features new visual artworks, in both two- and three-dimensional forms, from students at Carnegie Mellon University’s School of Art. Even art can be as “permanent” as a classical statue, or as temporal as a digital photograph. And fleeting, too, are gallery shows: Catch this one before April 1.