A flip book, flipbook, flicker book, or kineograph is a booklet with a series of images that very gradually change from one page to the next, so that when the pages are viewed in quick succession, the images appear to animate by simulating motion or some other change. Often, flip books are illustrated books for children, but may also be geared toward adults and employ a series of photographs rather than drawings. Flip books are not always separate books, but may appear as an added feature in ordinary books or magazines, frequently using the page corners. Software packages and websites are also available that convert digital video files into custom-made flip books.