The Busy Beaver game, pointless? Or a lesson in the problems of computability? - How do you decide if something can be computed or not? Professor Brailsford's code and further reading: Turing Machine Primer: Busy Beaver Code: Ackermann Follow Up: Original 'Ackermann' Film (Most Difficult Program to Compute): This video was filmed and edited by Sean Riley. Computer Science at the University of Nottingham: Computerphile is a sister project to Brady Haran's Numberphile. See the full list of Brady's video projects at: