The Crossword That Took the Whole Train

On a Monday in March, somebody left a newspaper on the 7:42 with the crossword half done. Nine answers had been filled in, neatly, in blue ink. Beside the grid, in the same hand, was a short note: Cannot get 14 across. Over to you.

Tomás found it on the window seat when he got on at the second stop. He was not a crossword person. He looked at 14 across for four stations, said the answer out loud by accident, which was OTTER, wrote it in with a pencil from his bag, and then, feeling that something had been asked of him, added a note of his own under the first one: Got it. 9 down is beyond me. Leaving it on the seat.

By Tuesday the paper had moved to the luggage rack, and three more answers had appeared, in green. On Wednesday a fourth handwriting joined in, small and very confident, and someone corrected a mistake in the corner with one tidy line through it and an apology in the margin. The notes grew into a column running down the side of the page. Nobody signed them. Nobody needed to.

The guard noticed on Thursday. It was his job to check the carriages at the end of the line, so he picked the paper up, read the column of notes, and put it back exactly where he had found it. On Friday morning a small card had been tucked inside, written in the guard's own capitals: PLEASE DO NOT REMOVE. PUZZLE IN PROGRESS.

The last clue, 22 down, held out until the following Monday. It was finally solved by a teenager on the way to school, who wrote the answer in pencil, underlined it twice, and added, under the long column of other people's handwriting: Done. Who started this? Nobody on the train ever answered. But the Monday after that, on the same seat, there was a fresh newspaper, folded open at a fresh puzzle, with one answer already filled in, in neat blue ink.

The story is invented, but the feeling behind it is a familiar one. An unfinished puzzle has a pull that is hard to ignore, and anyone who has left a half-done crossword on a staff-room table knows it rarely stays unfinished for long. Crosswords have been working this trick for a long time: the first one appeared in a New York newspaper in 1913.

What the passengers share is real as well: the small, anonymous kind of cooperation that happens between people who never actually meet. Leaving a book on a bench for a stranger, holding a door for someone a few steps behind, adding one answer to a puzzle and passing it on. None of it is arranged, nobody gets the credit, and it works anyway, which may be the most satisfying clue of all.