This summer, when cameras at the Tokyo Olympics zeroed in on the British diver Tom Daley, he was nearly always knitting: by the pool, in the stands, on the bus.

The needles and yarn became Mr. Daley’s signatures, second only to his newly minted gold medal. BuzzFeed deemed his crafting worthy of its own Olympic honors. On social media, knitters, crocheters and would-be crafters swooned over his calm demeanor and steady stitches.