Back in the olden days, Colin entered a proof without words in the Big Mathoff. It was mentioned, in passing, in a New York Times obituary of John Horton Conway.
Proofs without words are lovely, if your geometry is super-sharp and you can read between the line segments and follow the implicitly-made arguments. This video is for the benefit of those who don’t see it quite so immediately, and goes through the reasoning in more detail.
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