A genial outlook on life goes a long way to endear a play to its audience in cynical times—just ask Chekhov. And Annie Baker’s Circle Mirror Transformation, under Andrea Allen’s sensitive direction, does deliver dozens of gentle, pleasingly human moments via the gimmick of a small-town community-theater class. The extraordinarily good acting that underlies the characters’ amateur acting makes this pastiche of awkward nano-scenes engaging, despite its generally low stakes. As the four students and their hobbyist teacher Marty (Gretchen Krich) grope toward self-discovery through drama exercises, the only adversary is their own resistance to the process. During the six-week class (for us, nearly two hours, with no intermission), couples form and dissolve, memories are dredged up, and truths are disclosed.

Allen doles out the quirks like Halloween candy to each character. Teenage Lauren (the ravishing Anastasia Higham, in her first pro role) is all involuted angles—even her toes fold under her feet trying to hide. Spastically extroverted 30-something Theresa (Elizabeth Raetz), a former professional in New York, strikes poses constantly, well aware of her magnetism. As the recently divorced Schultz, Michael Patten again proves himself a specialist in humanizing wooden characters; his befuddled student is like a man who wakes from a coma on Mars.

As in some Christopher Guest movies, the main subject of this critically acclaimed 2009 play is how the shared activity—in this case a theater class, but it could just as well be a dog show—binds such disparate individuals. However, Baker’s conceit starts to crumble after the umpteenth group exercise. There’s not much structure or dramatic collagen to unite these episodes. Marty alludes to this disappointment after a game in which the class tries to compose a coherent tale by each contributing a word: “OK, maybe next week we can make it feel like a real story.” Perhaps in her next play this talented but tentative young playwright will do just that.