The story in three lines. Lan and Inkling arrive on a coral island in the Marshall Islands, long ago. A boy there must say when the next island is near, before anyone can see it. Pointing fails out at sea, and a picture of the waves in the sand half works until the tide takes it. Lan asks whether the waves could be made of sticks that stay. Then she asks where the two bent sticks cross. The boy learns the map by heart and leaves it on the beach. At sea he feels the island coming in the rocking of the canoe.

One question to ask. "Why did the sticks work when the sand did not?" Then: "Why did the boy leave his map behind?"

One thing to do at the table. Make a map of a room you all know with things from the table: a fork for the door, a cup for the sofa. Ask someone to look at it, shut their eyes, and say which way to walk.

The grown-up layer. The idea is that a map is a small picture of where things are, so you can find your way without seeing the place. The stick charts are real. They are unusual among maps: they show the movement of the sea, not the land. And they were learned by heart, not taken on the voyage. This time Lan says the answer too soon and it buzzes, so the story is also about going first with a question. The Honest Page says the knowledge was kept in families and learned over years. It also says nobody knows when the first chart was made.