I borrowed a calculator, it told me to be joyful always. Over the years, I’ve gradually discovered some neat things on a calculator. Like linear regression, when you finally understand what all those greek symbols above some buttons are for. Stored memory, very useful during linear interpolation in JC, Newton-Rhapson I think. Oh somehow this reminds me of sitting beside a window in a flimsy container of a classroom with black scratches on the wall left by careless students who sit near the windows and push the flippable lecture-style tables attached to their chairs against the walls when they fidget, or when they noisily push through to get to their seat, or a whole number of other conceivable situations where a table might meet a wall. An insert button, to a 12 year old equipped with a scientific calculator for the first time, it might have been miraculous to discover you didn’t have to start all over again, simply *gasp, oh look, a running display!* insert where needed. Racing with your classmates in punching all those numbers from 1 to 9 twice, and 5 twice more, to see who could add up to 100 first. Or discovering that mystical sequence of buttons that turns the calculator off and isn’t in the booklet. This last one is quite hazy to me, it could even be an attempt to embellish my past, but I suspect not: a secret function that does something I now cannot remember. This one is probably the hardest to do.