Heiroglyphics on the pavement

It was just another grueling day at the GUI, interspersed with checking another exam paper and trying to translate a bit of Latin. Then we went out to meet chums from down south who were up visiting their daughter - we ended up having a very pleasant meal in the Roseleaf, second week running! It was even busier than last week, though; lots of young ladies of a certain age talking very loudly and drinking cocktails. Well, after a couple of pints we probably started talking loudly and speaking in course codes.....

I saw this strange thing on the pavement while I was waiting for D who had kindly popped back up the stair to retrieve my phone.