the answer is simple — changing social situation and needs along with the burst of the chemical industry, allowing to create new textures, new products, and concepts. that too, for each and every traffic signal. before i get into everything, i just wanna say something really quick. kerosene is a common fuel for domestic heating systems. we want to focus ourselves as you suggest. i did, however, think that my work was so good that little would have to be changed if anything. or at the end of a fire that destroys a forest, there is a chance for a new forest to grow. 