On the way home from the grocery store just now, I was stopped at a red light at Market and Castro. Market is quite wide at this point, and the walk light never lasts long enough for you to get all the way across. A woman was jogging to get across in time, and with her plastic shopping bag, she acheived two perfect bars of music.
It’s a fast, slightly modified 3 – 2 clave. After the first phrase her steps got longer and slower, and the shopping bag dangled arrythmically. Then the light turned green.