My office overlooks a building site (new biological sciences building). One of the workmen has just sprayed onto the mud the message “LEE the crane driver IS A BATTY BOY” in letters large enough for (presumably) Lee to see from his vantage point in the cab of the tower crane.
The message has now been partly erased (another layer of clay and a JCB driving over it will do that), so leaving it as a riddle for future archaeologists.