Ключевые слова: advertising, all, backdrop, background, billboard, blackboard, board, border, chalk, chalkboard, class, classroom, clock, college, communication, composition, concept, copy, design, dirty, drawing, education, element, flat, frame, graphic, green, hand, learn, letter, menu, message, note, notebook, pattern, school, set, sign, space, stationery, student, study, symbol, teaching, text, texture, top, wallpaper, write,