Numerous devices which successfully displayed animated images were introduced well before the advent of the motion picture. These devices were used to entertain, amaze and sometimes even frighten people. The majority of these devices did not project their images and accordingly could only be viewed by a single person at any one time. For this reason, they were considered toys rather than being a large scale entertainment industry like later animation. Many of these devices are still built by and for film students being taught the basic principles of animation.