If the computer is a universal control system, let's give kids universes to control.
-- Theodore H. Nelson (Nelson 1974)
The substrate of LiveWorld, upon which the agent systems were constructed, constitutes a general purpose computational medium, designed for liveliness and ease of construction. LiveWorld consists of a tightly integrated object system and interface, which permits ready manipulation of the various components needed to make animate worlds. In addition to making the animated graphic objects or actors easy to create, manipulate, and control, it was necessary to make the internal parts and operations of the objects and the programs that drove them visible and manipulable as well. While LiveWorld itself is not based on agents or animate metaphors, it provides a world in which languages and programs based on those metaphors can be developed.
Note: this chapter goes into a good deal of detail about the inner workings of LiveWorld. Readers who are interested only in the agent systems may wish to skip over all but the first section of this chapter. The first section is an overview which introduces enough of LiveWorld's terminology to make the next chapter understandable.