Ключевые слова: advertisement, background, black, blackboard, business, capitalism, chalk, chalkboard, class, classroom, communication, concept, country, creativity, demand, drawing, economic, education, employment, empty, enterprise, frame, free, handwriting, history, ideas, imagination, industry, labor, letter, market, message, money, offer, ownership, paid, pattern, politics, private, property, retro, revenue, schoolhouse, stock exchange, supply, surface, system, text, textured, trade, writing,