The best symbols in writing often aren't drawn from our existing systems of symbolism: they're unique to that story, naturally imbued with meaning by the story's events.
If you're already writing with the Twelve Days of Writing, use the story you're working on. You can pick three objects already in your story or use the objects I suggest. (Pick your objects before you read on.) If you're starting writing here, this is your premise: Why did the protagonist fake those maps?
Match each object to any of the meanings. Each pairing then gets three scenes: how did the character first encounter the object? what happened to give it that meaning? what happens once it has its meaning?
If you want to write prose, pick one of the pairings and write its three scenes. If you want to story-map, sketch out the scene events for all three pairings, then see how they fit together into a story.
Tomorrow we're writing with... Themes.