There used to be an excellent tutorial on this subject, created by a gentleman named Al Placette. It
resided on his web site, while he was at Purdue University.
One day, the web site was no longer there, and the tutorial disappeared. Recently, with the help of
the Internet Archiving Project (the 'Wayback" machine) I
re-discovered it. I've taken a copy of his original work and reproduced it here (it's too good to risk it
getting lost again). I have taken the liberty of modifying the original pages, to remove the links to the
Purdue site that no longer function.
I hope you find the tutorial as informative as I did!
Start the tutorial -->here<--.