Ready for a fresh set of puzzles? Click here for the July/August 2025 Puzzle Corner, brought to you by guest editor Ed Faulkner ’03. Send problems, solutions (by August 1), and comments to puzzlecorner@technologyreview.com. Editor emeritus Allan Gottlieb ’67 launched Puzzle Corner in 1966. Find back issues through 2022 at cs.nyu.edu/~gottlieb/tr and more recent back issues at technologyreview.com/puzzle-corner.
The other day I idly opened TikTok to find a video of a young woman refinishing an old hollow-bodied electric guitar. It was a montage of close-up shots—looking over her shoulder as she sanded and scraped the wood, peeled away the frets, expertly patched the cracks with filler, and then spray-painted it a radiant purple.…