[S0122017]

It does not appear to be any of the ancient texts – but does bear a remarkable resemblance to the old Hobo signs.

What, for real?

[R. Scott]

Yep. I remembered some from back in the 50s when hobos were still commonly riding the rails. Several years ago I picked up a book (Dictionary of Symbols by Carl G. Liungman, ABC-CLIO, Inc) that included a section on those.