This is timely -- the question, "Are Graphs the Primary Data Structure in Nature?" came up on Quora a few days ago (http://www.quora.com/Are-graphs-the-primary-

This is timely -- the question, "Are Graphs the Primary Data Structure in Nature?" came up on Quora a few days ago (http://www.quora.com/Are-graphs-the-primary-data-structure-found-in-nature http://www.quora.com/Are-graphs-the-primary-data-structure-f...).