alt Hacker NewsI'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.
My father taught me times tables, each one written on the back of a fag packet, in 1972. And we used matches for addition and multiplication before that.