Ключевые слова: audience, audiovisual, background, beam, black, blue, board, business, cable, ceiling, classroom, college, computer, conference, corporate, digital, education, film, gray, grey, hang, home, lcd, leacture, led, lens, light, modern, mounted, movie, multimedia, overhead, photographic, plug, presentation, projection, projector, roof, room, screen, slide, technology, video, viewer, white, working,