William Ensign Lincoln invented the definitive zoetrope in 1865 when he was circa 18 years old and a sophomore at Brown University, Providence, Rhode Island. Lincoln's patented version had the viewing slits on a level above the pictures, which allowed the use of easily replaceable strips of images.
The zoetrope works on the same principle as its predecessor, the phenakistoscope,
but is more convenient and allows the animation to be viewed by several people at
the same time. Instead of being radially arrayed on a disc, the sequence of pictures
depicting phases of motion is on a paper strip. For viewing, this is placed against
the inner surface of the lower part of an open-