12 Favorite Problems
A concept given forth by the Nobel Prize winner, bla bla bla Feynman
The idea here is that you keep 12 problems in your life that you are working on at all times. Some can be related, others worlds apart. Doing this can lead to serendipitous events that causes breakthroughs on one or more of the problems you have in front of you.
A series of articles by Tiago Forte