“Prime numbers are useful for writing codes and in America they are classified as Military Material, and if you find one over 100 digits long, you have to tell the CIA and they buy it off you for $10,000. But it would not be a very good way of making a living.

Prime numbers are what is left when you have taken all the patterns away. I think prime numbers are like life. They are very logical, but you can never work out the rules, even if you spent all your time thinking about them.”

—from The Curious Incident of the Dog in the Night-Time by Mark Haddon