Sandwich Bag Graffiti

A little while back, toward the end of December last year, I did a long stretch of days where I needed to change my routine a bit to take advantage of a window of time that came up that I could use for pushing forward on the book. I was falling behind and desperately needed to improve my daily production rate of finished art in order to catch up. So, I ended up ditching making a sandwich in the morning, instead leaving very soon after getting up to head to my office. I then stopped taking my sandwich altogether when I ran out of bread and did not make the time in the evening to bake a fresh batch, as I do once a week or so, because I was just coming back home and falling into bed.

The USC catering outlets were all closed that week. This meant that I ended up seeking out a place to buy a sandwich near my office. I found a place called something like WhatWich or WhichWich or WhyWich or some other abominably annoying name like that, but they did good sandwiches. It is one of those places that offers far more options than I care to have to deal with: You take a break for lunch and you have to fill in a page long form. How fun is that? The paperwork is the sandwich bag itself (good idea actually – no extra paper needed). Well anyway, one day while I waited for them to prepare my order, I wandered around and found a wall on which people had posted drawings and other scribblings, done on the house bags. I rather warmed to the place a bit after that – they encourage people to draw, unselfconsciously, and share. We need more of that in the world. Of course, I had to join in. My sandwich was almost done, so no time for anything elaborate… what to do? Then I heard my grad-student self speak up from deep (ish) inside and suggest doing what I did a lot, back in the day: Share a current favourite equation with the world (whether it asked me to or not*!). So I did. In the above compound picture, on the right you’ll see the cute formula I found last year for the efficiency of a kind of black hole heat engine. [I also showed how to insert it into an algorithm that will compute the efficiency of a black hole heat engine defined by an arbitrarily shaped cycle. (See here.)]

I wonder how long it stayed up?

-cvj

*Yeah, paper napkins in restaurants, bit of discarded newspaper, unattended chalkboards, etc. I was a menace.