Parrallax,thanks for your post. Nice to read some good stuff on this forum. I visit frequently only to be turned off by the usual suspects. I have made one or two feeble attempts to post something other than the usual,alas the ground was fairly barren. This is education for me,as I was never taught Critical Thinking,just tried to get it right as I went along. I will have a look at the reference,thanks again.
