Back in 2010, Smashing Magazine published a good/popular blog with a Drupal cheat sheet background image.  Fast forward three years to current year of 2013 and we need an updated version for Drupal 8.  This should be a fairly simple task by going to api.drupal.org, finding each function in Drupal 7, then finding it in Drupal 8. In this task, DO NOT create a Desktop image. This task is concerned finding the new Drupal 8 functions not listed and need to be listed.

http://www.smashingmagazine.com/2010/06/14/drupal-cheat-sheet-wallpaper/

NOTE: If unfamiliar with Smashing Magazine...go read it.