Ключевые слова: abstract, advertising, announcement, antique, background, billboard, black, blackboard, blank, board, business, chalk, chalkboard, class, classroom, color, concept, copy, drawing, dust, educate, education, empty, frame, green, hand, horizontal, isolated, learn, lesson, lines, man, message, old, pattern, presentation, red, retro, school, slate, smudge, space, studying, teach, texture, textured, vintage, wall, wood, wooden, work, write,