Ключевые слова: backgrounds, barrel, blue, bricks, chemical, chemistry, chimney, clean, clouds, coal, construction, diesel, dirty, energy, engine, environment, equipment, factory, flue, fog, fossil, fractional, fuel, futuristic, gas, gasoline, industrial, industry, manufacturing, metal, natural, nature, oil, part, petrochemical, pipe, pipeline, pollution, power, refinery, science, shell, skies, smoke, steam, steel, technology, towers, white, working,