Ключевые слова: art, atom, barrel, canister, color, colorful, construction, contour, danger, dollar, drop, energy, finance, fire, flame, fuel, gallon, gas, gasoline, geological, geology, hat, icon, illustration, industry, isolated, jack, leak, line, linear, liquid, mark, molecule, money, oil, outline, petroleum, pop, popart, pump, recovery, research, rig, safety, science, set, triangle,