Pulaski Academy football coach Kevin Kelley never punts. He always kicks on-side. His teams play … weirdly. Now the Arkansas squad is going back to Dallas to face its rival, Highland Park, a team that has won 84 games in a row at home and outplayed Pulaski Academy last year. Will Kelley’s data-driven plays lead to the win? The latest film in FiveThirtyEight and ESPN Films’ short-documentary series Collectors, “Undefeated,” directed by Jamie Schutz, follows Pulaski as the team adds a new wrinkle to its playbook and tries to end Highland Park’s streak.