Dave Avery, left, and Justin Bishop load shells into three-inch mortars during setup for the Fourth of July fireworks show Wednesday afternoon at the Big Horn Equestrian Center. Each mortar shell is fired according to a timed sequence set by the firing control computer. The fireworks display is timed to by choreographed with music that will be broadcasted over the air by local radio during the show. Bruce Burns with his crew of certified pyrotechnics and volunteers have been working all week to get ready for the popular fireworks display at the polo fields. The fireworks show will light up a 10 p.m. Friday night.