"Shave and a haircut, two bits." Ah those were the days! We know that a quarter is also known as "two bits," and that when a shave and a haircut was a quarter, it was back in the 1930's and earlier. Actually, that shave and a haircut for two bits, was the common price for over a hundred years!
American captives in the Vietnam war would authenticate a new prisoner's American identity by tapping the first 5 notes of "Shave and a Haircut," against a cell wall, waiting for the appropriate response two bits. American POWs were then able to communicate securely with one another via the quadratic alphabet code.
"Shave and a Haircut" is often used as a means to attempt to communicate with spirits in the supposedly haunted location. An investigator will tap out the first five notes, and the return of the last two is taken as confirmation that an intelligent spirit is present.
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