The Yamamote Line in Tokyo is the circular elevated subway line that circles the city. If you ride it at night, or even during the day, you will find many passengers deep in slumber, as if the flashes of light barely illuminating their faces were nothing more than a projection of their fleeting dreams. In Japan, the shadows and silhouettes walking the streets wander half asleep without looking up. Sleepwalking is a sleep disorder in which people perform motor activities while remaining unconscious and unable to communicate.