@tcql I looked it up, apparently it was. "ETOPS and systems functionality and reliability test for the Rolls-Royce Trent 1000 Ten engine." https://twitter.com/jonostrower/status/893155797122732032 http://aviationweek.com/awincommercial/boeing-traces-787-shaped-flight-path-across-us
I guess they just needed to keep the plane in the air for a while, so might as well have fun with the flight plan since they don't care where they're flying.