Ключевые слова: arena, board, boards, cellular, concert, crowd, crowded, crowding, crowds, electronics, entertainment, exhibition, footlight, footlights, lamps, light, lighting, lighting system, lights, limelight, live, live concert, mobile phone, music, people, performance, person, phone, playing, scene, show, smart phone, smartphone, spectacle, spotlight, spotlights, stadium, stage, system, technology, telecom, telephone,