Walden Theatre graduates reunite on stage in several productions this summer, starting with David Mamet’s “American Buffalo.”Walden has been turning out well-trained young actors from its conservatory program since 1976. They go their separate ways after graduation, but this summer they’ll have several opportunities to work at Walden again.2008 graduate Ben Park, who went on to earn his BFA in acting from Northern Illinois University and is teaching at Walden this summer, will join Elliott Cornett (Walden ’08) and Jacob Lyle (Walden ’10) in a production of David Mamet’s “American Buffalo” this weekend.The play revolves around three incompetent men who conspire to steal a coin collection and end up stumbling over their own ambitions. Park says when the plot goes sour, as it usually does in Mamet’s gritty plays, what happens is nothing short of chaos. “People can relate to the ensuing chaos a person can so easily get into by simply not being as informed as you should be,” says Park. “These are there guys who think they have everything figured out but are completely clueless.” Park, Cornett and Lyle acted together for years at Walden before going on to different college acting programs—Park to Northern Illinois University, Cornett to the University of Louisville and Lyle to DePaul University. They were anxious to act together again and approached Park’s father, veteran director Hal Park (who stage managed the West Coast premiere of “American Buffalo” in 1978) to direct. Park says because he and his cast-mates have such a long working relationship through Walden, they felt ready to tackle roles written for more experienced actors.“With Mamet, you have this rhythm that’s almost like Shakespeare. Mamet writes with this natural rhythm, and if you can pick that up you can really figure out the play. I think that’s something we picked up quicker than most people would have because we’ve been working together for so long,” he says.The production runs Friday through Sunday at Walden Theatre. It kicks off a summer of alumni performances, including a comedy sketch show and a one-act play showcase.