Ключевые слова: art, butterfly, button, can, car, clip, computer, concepts, conservation, crane, decoration, design, drops, earth, ecology, element, energy, environment, factory, flower, foliage, forest, fork, house, icons, illustration, image, lamp, leaf, leaves, mill, natural, nature, plant, poultry, power, radiation, recycle, recycling, set, sign, symbol, thermometer, trash, tree, vehicle, water, wind,