[jiggyboy]

"FlightRadar24 is an app and website which tracks the flight path of every plane currently in the air. On March 12, 2015, someone using it noticed an interesting path being carved into the skies over Lakeland, Florida."

http://www.cracked.com/blog/4-people-who-put-massive-effort-into-drawing-dicks/

[ops33]

“Visually, the plane circled in a racetrack-style oval shape over the City of Denver at roughly 32,000 feet several times.”

Sounds like enroute holding.