I came across hobo symbol system in Richard Sproat‘s „Symbols: An Evolutionary History from the Stone Age to the Future“. In an overview of non-linguistic symbo

I came across hobo symbol system in Richard Sproat‘s „Symbols: An Evolutionary History from the Stone Age to the Future“. In an overview of non-linguistic symbols systems he groups hobo signs with Gaunerzinken, signs used by German-speaking vagabonds. The body of research for them was more skewed towards crime as most analysis was done as part of police investigations. Would really recommend this book as a non-professional level introduction on the topic.