Ключевые слова: art, attention, background, black, blank, blue, caution, clear, cloud, clouds, cloudscape, cloudy, communicate, communication, concept, copy, copyspace, danger, day, diamond, direction, drive, empty, hazard, highway, horizontal, icon, information, message, metal, nobody, notice, outdoor, pole, post, road, safety, shaped, sign, signpost, sky, space, street, symbol, text, traffic, transportation, travel, warning, yellow,