Ключевые слова: abstract, alkane, atom, backdrop, background, black, blackboard, chalkboard, chemical, chemistry, concept, draw, drawing, education, effect, element, formula, fuel, futuristic, gas, graphic, greenhouse, hand, illustration, lng, marker, methane, molecular, molecule, nobody, object, pattern, pen, research, school, science, scientific, scientist, screen, sign, sketch, slate, structural, structure, symbol, technology, text, wallpaper, whiteboard, write,