“I’m the kind of person who recycles materials,” says the assemblage artist Betye Saar, “but I also recycle emotions and feelings.” Saar’s work—found objects arranged in frames, boxes, and tableaux—can seem as homespun as a folktale, but the tale she tells is shadowed by racial and sexual oppression. How did Saar’s emotions become creations? “Call and Response” moves from the artist’s preliminary sketches to their materialization as art. —E.C.