Semaphore Flagging & Hobo Sign

[230gr]

Thesis might be useful.
Semaphore Flagging
For sending messages visually with two bright flags or cone lights.


Hobo Sign
This dates back to the 1930s when Hobos wished to left information for other transients. They were scratched or chalked onto curbs, sidewalks, etc in obscure locations. Might be useful again.