Ключевые слова: address, art, background, box, business, communication, concept, container, correspondence, delivery, design, document, email, empty, envelope, flag, flat, guidepost, icon, illustration, inbox, isolated, letter, letterbox, mail, mailbox, mailing, message, metal, newsletter, object, office, open, package, paper, post, postage, postal, postbox, receive, send, service, set, sign, symbol, traditional, white,