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