Ключевые слова: broadcast, color, colorful, communication, computer, connection, contour, document, drop, faucet, green, icon, illustration, internet, isolated, lamp, light, line, linear, machine, number, office, outline, paper, print, radio, safety, semaphore, set, sign, signal, smart, stop, stoplight, symbol, system, technology, thing, transportation, urban, warning, water, wifi, wireless, xerox,