I documented my dérive poorly in the moment, partly because I was distracted by the land around me, and partly because it grew dark and my little phone camera is not well suited to low light photography. I will try to recall all of the places I went and the things I saw.

I began on Sproul Plaza in Berkeley, a very familiar place from my college days, but I was determined to discard all the well-worn paths of my memory and strike out in new directions. And so I struck out not for my Telegraph haunts, or for the engineering buildings on the east side of campus, but due north, toward the part of Berkeley that I had never once explored in the years that I had lived there.

One block past the edge of campus, I turned left, trying to avoid traveling in too straight of a line, and in a block encountered the Pacific School of Religion, of whose existence I had not previously been aware. The campus was mostly deserted, the buildings dark, but here on the grounds were a fencing student and her teacher, hard at work. Further on, a young couple playfully wrestling on the grass, taking advantage of the warm dusk and the relative solitude of the empty school.

When I emerged on the other side of the PSoR campus, I turned to the north again, pressing further into unfamiliar territory. I noticed that the north side of the campus felt completely different from the south side, not at all like a "college town". Mostly residential, with large single-family homes (most of them beautiful and fairly old-looking). It's almost as if the college students just follow the pull of gravity and drift downhill, toward the south, and the landscape reflects that.

At some point I wound up on Euclid Avenue heading north, and came to what my iPhone map told me was Codornices Park. It was here that I found my first cryptic sidewalk chalking of the evening, and photographed it for later study.

It was starting to get dark out by this point, and having walked steadily uphill for more than a mile I was tempted to head back down, but no, I told myself, drop your usual (lazy-ass) motives and look for something new. On my map I saw another park, La Loma, and felt instinctively drawn to it. Good enough.

I proceeded up Rose Street, and found that the apparent short distance on the map was deceiving -- the grade was steep, straight up into the Berkeley hills. The street eventually hit a dead end, hitting too steep of a grade in the land for cars to climb, with steps for pedestrians to get up to the next terrace of street, which was in the form of a concrete overpass. Here I saw more chalking, possibly by the same scribbler from earlier, but this time in ancient Egyptian.

I passed the steps by and continued uphill to investigate the space under the overpass; it looked like something a troll might live under, or maybe a good place for local teenagers to drink and smoke away from adult eyes. The wealth of graffiti supported my theory. I also found that if you had gotten that far and didn't feel like walking back down to the steps, you could climb up over a rail and get to the street above.

As I neared La Loma Park, I looked back, and was amazed at the view from that height; the entire bay stretched out before me. Do people know this is here, I wondered? I imagine the immediate locals who live up in those hills know all about it, but in my years as a student I'd never come up this high, even though it's not really that far.

The park itself was deserted, except for a few deer (who were not quite tame enough to let me walk up and snap a good picture). I walked around it for a little while, enjoying the silence and the view, and made a mental note to come back some other evening, maybe with a picnic dinner.

As I left the park, I found another sidewalk chalking, definitely by the same hand as the first one. Were they going from park to park? Had they followed my route exactly (or its inverse), and done the cartouche as well? I will probably never know.

Feeling satisfied with the altitude I'd reached, I allowed gravity to take over, and went straight down the hill. More beautiful houses and funny little staircases, and the occasional sleeping homeless person (somewhat surprising that far from Telegraph, but maybe the absence of foot traffic makes it better to sleep in; I didn't see a single other pedestrian on this part of the walk, I don't think).

As I reached the campus, the landscape abruptly shifted, and I started seeing people everywhere again. I passed all the familiar buildings in a blur, remembering the classes I had taken in that one, the graduation I went to in that one, the first time I went to that restaurant there... and then I was back at my car, and twenty minutes later, home in San Francisco.