The story in three lines. Lan and Inkling arrive on a mountain road in the Andes, where a girl must send her village's count of three hundred and twenty-four sacks down the mountain through four relay runners. A whispered count comes out as three hundred and forty-two, and a bag of pebbles spills. Inkling asks what could stay the same in every hand. Lan asks whether the count could be tied into a cord, and the girl ties the hundreds, tens and ones in their own places.

One question to ask. "Why did the whispered number change?" Then: "What do we write down so we don't have to remember it?"

One thing to do at the table. Play the whisper game with a three-digit number around the table and see what comes out at the end. Then tie the same number in knots on a piece of string, one group of knots each for the hundreds, tens and ones, and pass that round instead.

The grown-up layer. The idea is a record that does not depend on memory: a message that passes through many hands should travel in something that cannot change. Knotted cords in the Andes held numbers this way, with the place of each knot showing ones, tens or hundreds, like the empty-place idea in book 8. The Honest Page says knotted cords are much older than the runners' roads, and that nobody can read everything they say. This time Lan says the answer too soon and it buzzes. The third word under DOOR and OPEN grows: W, then I.