Today, computers are commonly used in mathematical research in areas that require complex calculations. This is relatively new, however, and has altered the way mathematicians think about proof. One of the most famous examples of mathematicians using a computer to help to prove that something is always true is the ‘Four Colour’ theorem. The problem states that when constructing a map so that no two adjacent countries are represented by the same colour, only four colours or fewer are required to allow this to be true. In 1976, Kenneth Appel and Wolfgang Haken (Wilson, 2003) used coding to show that this was always true for any map you could ever create.