When I studied abroad in Switzerland, I took a weekend trip to Milan, Italy. We rode the train into their main station and then used their underground to get to the Piazza Duomo. Coming up the stairs from the station to the Piazza, you walk up a flight of stairs that has piano keys on it that play the tone you are stepping on. This is a really interesting way to advertise a music store. However, the one draw back is that most people going to that station are likely tourists who won't be buying musical instruments. Also, many people will be so excited by the how cool the experience is and won't pay attention to the company promoting their product. Even when I searched google for photos of the musical stairs, I could not find even one picture with the name of the company who paid to install the stairs.