How things change

Katherine's boyfriend in Mexico apparently does foreign currency trading for fun. She tried to get him to explain to her how it works but he wouldn't, seemed to assume she wouldn't know what he was talking about, so she just called me and got me to explain the idea and the math behind it. She said 'OK, good, I don't need to understand it as long as you do, so combined we're still smarter than everyone else."

Still, I never figured I'd find myself explaining how you can animate a 3 dimensional graph to show changes over time and then make a graph of the change to Katherine. Her boyfriends back home were more experts at how to do wheelies on motorcycles or how to sweet-talk a policeman.