Thank you, I'm glad you got the concept. I must admit I was in the wrong as well. I am sorry I came off as peeved. I realized after a little bit that I had fallen victim to the "curse of knowledge" phenomenon. That may have been the first time in my life that I realized that had happened. Sometimes (in general) people don't understand things for different combination of reasons; i.e. poorly explained, unfamiliar content, etc. and I had forgotten that. I've never really been that great of a teacher either. Again, sorry I was impatient. On a better note, feel free to ask me any questions if you have them.