If you see something, say something.
Waiters at restaurants will often ask if people want anything from the menus by saying, e.g., "see something you like?" ---but this restaurant is on the new york subway station, which broadcasts "If you see something, say something." as a terrorism fighting message, e.g., if you see someone doing something that could potentially be dangerous, the message encourages riders to say something and contact a number. The restaurant and subway intersect via this message: "if you see something [on the menu you want to order], say something [to the waiter]"