Ключевые слова: abstract, advertisement, back, background, backgrounds, bare, black, blackboard, board, chalk, chalkboard, classroom, close, closeup, communication, concepts, copy, design, dirty, distressed, drawing, dust, education, empty, frame, front, grunge, horizontal, industry, learning, macro, message, nobody, old, pattern, people, photo, photographer, rampart, rough, rubbed, school board, space, surface, texture, textured, view, wallpaper, white,