Ancient civilizations had a really good way of drawing attention to certain things - they marked them. They used whatever was at their disposal at a given moment to make something visually stand out. This can come in handy when trying to point out things in the real world. This person, for instance, had lost his car keys, only to find out that somebody had marked them out for him on the street.
We do have to admit that this move is not only incredibly kind, but it's also kind of ingenious. We'd probably never think to mark something out like this on the street.