Beams? Green colors? There’s a method to this madness. “It’s a neurological drill,” Curry summarizes. He’s talking about his use of the FitLight trainer, an increasingly popular tool among athletes and teams . The system boasts portable lights, manifold of color, capable of being activated and deactivated by touch. It also sends instant, downloadable data about the workout. The flashing lights train you to react, to focus, to choose.