“His recipe for success is to have 4 problems on the go: a big problem, difficult and important, that will probably depress you before it makes you successful; a workable problem, tedious but with a clear strategy so you can always make some progress and feel a sense of accomplishment; a book problem, for the book you're writing or may eventually write; and a fun problem, since life is hardly worth living if you're not having some fun.” pp. 114-115 Genius At Play: The Curious Mind of John Horton Conway by Siobhan Roberts, Bloomsbury Publishing 2015