There are a lot of casual relationships within our cities that allow us the joy of endlessly unresolved conversations about any number of issues or trends.

But here’s a great little talk by physicist Geoffrey West at TED last year about some mathematical constants embedded within ourselves and city life.  Fascinating stuff and some great foundational rules you can carry around with you the next time to come upon a difficult urban debate.

From cleaning yogurt off your counter to building a house, the “greenest” option isn’t ever obvious.

h/t: The Daily Dish