Steven Dietz in his 1996 play offers a lesson in epistemology by relating the story of an extramarital affair in loops: scenes that seem to be based in reality are later exposed as fantasy or as dialogue in a play. He also means to make his characters universal by divorcing them from specific situations. But Orion’s Left Foot doesn’t have the skill to pull off either the intended shifts in perception or the characters’ universality. Skating along the surfaces of their roles, the young ensemble, directed by Liz Cody, instead create generic, uninteresting, unbelievable characters. Through 9/2: Wed-Fri 8 PM. Cornservatory, 4210 N. Lincoln, 630-688-5611. $10.