Poetry and Mathematics -- Learning by Heart

     Many mathematical ideas are learned "by heart" -- that is, stored in  memory -- definitions, calculation, etc -- even for those who are not math-focused. 

      I grew up on a farm -- and, in addition to all of the learning opportunities related to farming, we had a book-case that included a set of Compton's encyclopedias, a collection of Aesop's Fables, and (my favorite treasure) Robert Louis Stevenson's A Child's Garden of Verses.   There are a number of these verses that I still know portions of "by heart" -- "My Shadow," "The Cow," "The Swing" -- and here is a two-line favorite:

       Happy Thought     by Robert Louis Stevenson (1850-1894)

       The world is so full of a number of things.
       I'm sure we should all be as happy as kings.