"Just send me a PDF!" - but what kind of PDF? As Professor Brailsford explains, PDF is simply a wrapper which can contain a variety of joys! https://www.facebook.com/computerphile https://twitter.com/computer_phile This video was filmed and edited by Sean Riley. Computer Science at the University of Nottingham: https://bit.ly/nottscomputer Computerphile is a sister project to Brady Haran's Numberphile. More at http://www.bradyharan.com/