Ключевые слова: announce, anonymous, attend, audience, auditorium, blur, community, concert, course, crowd, dark, dim, event, faceless, gather, group, hall, horizontal, illuminate, indoors, lecture, lesson, listen, meeting, men, modern, obscure, opinion, participant, participate, people, presentation, public, seminar, show, stage, strategy, support, unrecognizable, watch, women,