Hundreds of runners set off Friday evening on what might as well have been an infinity loop through Colt State Park, for the annual running of the Anchor Down Ultra. Unlike a traditional race held over a measured distance, Anchor Down measures the race with a clock — some runners planned to run 6 hours, which is already two to three times the time it takes an elite runner to finish a traditional marathon. Others planned to run for 12 hours. For the best endurance athletes, the goal was 24 hours.