I love these hobo symbols, they form such a basic signage system, simple and effective. It was developed by hobos in the 1950's who communicated with each other by drawing these images on the street in chalk.
You may remember a reference to them in Mad Men when a Hobo drew the 'Dishonest Man' symbol on the gate of the young Don Draper's house in a flashback scene.
The whole set can be seen over on World Famous Design Junkies
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