If you want a challenge, try writing a romantic message in hobo sign. Or even just a non-homicidal one. I recently tried making a little romantic note for Mrs. Bell. If I'd wanted to say: "be ready to defend yourself, there's no point going this way, owner will give to get rid of you" I'd have been all set. But that isn't exactly what I was going for. In the end, I settled on this:

In other words, "you can camp here, a kind lady lives here, the sky's the limit."

Although I was sorely tempted by "free telephone." Next on the list to try: semaphore and/or DNA.