since Christiaan Huygens invented this early image projector in 1659. Other Hydrotechnics: a technique that includes lights, water, fire, fog, and lasers, with high-definition projections on mist screens. Drawn on film animation: a technique where footage is produced by creating the images directly on film stock; for example, by Norman McLaren, Len Lye and Stan Brakhage. Paint-on-glass animation: a technique for making animated films by manipulating slow drying oil paints on sheets of glass, for example by Aleksandr Petrov. Erasure animation: a technique using traditional 2D media, photographed over time as the artist manipulates the image. For example, William Kentridge is famous for his charcoal erasure films, and Piotr Dumała for his auteur technique of animating scratches on plaster. Pinscreen animation: makes use of a screen filled with movable pins that can be moved in or out by pressing an object onto the screen. The screen is lit from the side so that the pins cast shadows. The technique has been used to create animated films with a range of textural effects difficult to achieve with traditional cel animation. Sand animation: sand is moved around on a back- or front-lighted piece of glass to create each frame for an animated film. This creates an interesting effect when animated because of the light contrast. Flip book: a flip book (sometimes, especially in British English, called a flick book) is a book with a series of pictures that vary gradually from one page to the next, so that when the pages are turned rapidly, the pictures appear to animate by simulating motion or some other change. Flip books are often illustrated books for children, they also are geared towards adults and employ a series of photographs rather than drawings. Flip books are not always separate books, they appear as an added feature in ordinary books or magazines, often in the page corners. Software packages and websites are also available that convert digital video files into custom-made flip books. Character animation Multi-sketching Special effects animation See also Twelve basic principles of animation Animated war film Animation department Animated series Architectural animation Avar Independent animation International Animation Day International Animated Film Association International Tournée of Animation List of film-related topics Motion graphic design Society for Animation Studies Wire-frame model References Citations Sources Journal articles Books Online sources External links The making of an 8-minute cartoon short "Animando", a 12-minute film demonstrating 10 different animation