An animation sequence is composed of a series of drawings. Each drawing differs from the preceding one so that when they are arranged in a stack and viewed sequentially, the images appear to flow naturally. In classic film animation, image drawing is done in two stages. The background for each scene is painted just once. Then, the cartoon characters and any other foreground objects are painted on transparent sheets of celluloid called cells which are placed over the background. With cells, animation can be achieved by redrawing only the parts of the scene that move while the background stays the same. Animation on the Amiga works similarly. The background is formed by the playfield while the objects that move can be conveniently handled with the GELs system. Animation Data Structures Moving the Objects Animation Types Your Own Animation Routine Calls Specifying Animation Components Standard Gel Rules Still Apply Specifying the Animation Object Animations Special Numbering System The AnimKey Animtools.h and Animtools.c Adding Animation Objects