This is my favourite explaination. I have had this bookmarked for over 10 years and keep coming back to it: http://www.felderbooks.com/papers/bell.html http://

This is my favourite explaination. I have had this bookmarked for over 10 years and keep coming back to it: http://www.felderbooks.com/papers/bell.html http://www.felderbooks.com/papers/bell.html