Can you write down all the digits of pi from memory? Where does pi come from?

Question: Can you write down all the digits of pi from memory? Where does pi come from?
- Keywords:
  memory,
  pi
Asked by anon-181914 on 17 Jun 2018.
- Claire Donald answered on 17 Jun 2018:
  
  Its definitely safe to say that I can’t! I usually round down to 3.14 which is a long way off the trillion digits beyond its decimal point.
  
  As far as I am aware pi has been used for thousands of years and is used to describe the ratio of the circumference of any circle to the diameter of that circle. Regardless of the circle’s size, this ratio will always equal pi.
  
  Personally I prefer the pies that come from ovens.

Question: Can you write down all the digits of pi from memory? Where does pi come from?