I'm pretty sure this first appeared in Gardner's "Mathematical Games" column in the March 1962 issue of Scientific American. Gardner later collected some of his

I'm pretty sure this first appeared in Gardner's "Mathematical Games" column in the March 1962 issue of Scientific American. Gardner later collected some of his columns and published them in books, which is what you see in this HN submission. [1] https://www.jstor.org/stable/24937263 https://www.jstor.org/stable/24937263