I attempted to show you were you could go to look up the info that you requested. I am not going to force feed it to you. The pages I sent you will shed some light on you issue if you will just explore and read them. The SDA has a good background and history of the art if you just go read it. If you can't find it or read then I will go and copy and past it for you. This method of force feeding information shows a lack of effort on your part and I would love to not have to resort to it. However, sometimes narrow minds call for desperate measures