Ключевые слова: address, background, black, box, business, communication, concept, contact, correspondence, delivery, design, drawing, element, email, envelope, flat, icon, illustration, inbox, information, internet, isolated, letter, letterbox, line, mail, mailbox, message, network, object, office, open, outline, paper, pictogram, post, postage, postal, postbox, receive, send, service, shape, sign, silhouette, simple, symbol, web,