Gyroscope

In the movie Inception, several characters enter another man’s dream, after that, they enter a dream within that dream, and, then, they enter yet another dream with a dream. One of the ways that the filmmakers make you believe you might be in a dream is having the characters in rooms that spin as one dream is affected by the reality around the sleeping person. The filmmakers used a gimbal to spin the room. A gimbal is related to a gyroscope.