Ключевые слова: background, cistern, concept, container, design, draw, drawing, earth, eco, ecological, ecology, electrical, electricity, element, energy, environment, environmental, fossil, fuel, gas, gasoline, generation, hand drawn, icon, illustration, industrial, industry, isolated, line, linear, minimal, nature, oil, outline, petrol, petroleum, pictogram, planet, pollution, power, purple, recycle, set, sign, symbol, tank, technology, thin, transportation,