The idea base on a sketch that I did on the previous day in the class. So base on that you can build up a concept for your project. I linked this piece of ink to a man wearing a hat and a long coat and he's definitely looking for something

That's how I imagine Sherlock Holmes searching for a hint of crime as he standing on London like he's in a board game. Every road is named after a story of Mr. Holmes and the other things on the map is also linked to London and the detective.