Think of the secret place where you want to hide the magic map of your island.
On a slip of paper write where the map is, e.g. My magic map is in the river. Don't show it.
Write instructions on how to get from the village to the secret place.
Give your map and instructions to another pair. They read the instructions and draw the route to find the secret place with the magic map. They write the answer to the question «Where is the magic map?» on a slip of paper.