Ready for a fresh set of puzzles? Click here for the September/October 2026 Puzzle Corner, brought to you by Michael S. Branicky, ScD ’95, of the Puzzle Corner Puzzle Crew (aka PC²), which also includes Edward Faulkner ’03, MEng ’04, and Abe Kunin ’03. This column includes solutions to the May/June issue.

Send problems, solutions (by October 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.