alt Hacker News> Really, though, is it impossible to imagine no one, ever, using a cigarette pack to jot something down? It's a colloquialism. It doesn't even have to be taken literally to make sense. What is gained by questioning it on that level?
I took the OP's question to really be a question about the origin of that phrase, and with your answer, I learned something I didn't know before. So I, for one, am happy the question was asked.
I'm glad it was asked too and enjoyed the answer.
The OP's question was clearly skeptical though:
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napkins, and envelopes at least kind of make sense.
Who was ever writing on the back of cigarette packs?
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Implication being that writing on the back of cig packs does not make sense. I'd agree with your reading if not for the "at least kind of make sense" bit.