With Irish and American actors, Sam Shepard riffs on Sophocles

At least a passing knowledge of Sophocles’ Oedipus Rex should be required before seeing Sam Shepard’s A Particle of Dread (Oedipus Variations) at the Pershing Square Signature Center. If you don’t know this ancient yarn, the new 85-minute drama, featuring a mixed company of Irish and American actors, will leave you pretty confused. Then again, if you are familiar with that Greek tragedy, chances are you’ll be a bit puzzled by this alternately brilliant and mindboggling take, which is directed by frequent Shepard collaborator Nancy Meckler. “Variations” is the imperative word here. Like jazz music, Shepard starts with a theme — in this case, the tale of the man who kills his father, inadvertently marries his mother, and gouges out his eyes in despair — and then riffs on it for a while. There are a series of interconnected plots, put together in the jagged-edged fashion of someone trying to reassemble a glass vase that fell off a shelf and shattered into a million little shards. A police officer and a forensic investigator (Jason Kolotouros and Matthew Rauch) attempt to solve a crime scene involving three dead bodies on the side of the road, some tire tracks, and a lopsided pair of footprints. An elderly paraplegic (Stephen Rea) tries to put this story together himself, to the chagrin of his wife (Brid Brennan), and grown daughter (Judith Roddy), who has significant problems of her own. And then there’s Oedipus himself (Rea again), whose storyline follows the Sophocles pretty faithfully.