Chapters * Title * Contents * Introduction * Place * System * Design * Using * Future * Bibliography
Sections
* Place * Constructionist * Evocative * Crystallizing * MediaFusion * Organizing * Why * Glass * Multiplayer * Reflection * MUD
Evocative Objects: Logo, StarLogo, Stella
StarLogo termites gathering wood chips into ever more concentrated piles
StarLogo (Resnick, 1994) is a language based on the childrens' programming language Logo. Logo, which was based on the
procedural language Lisp, adds a the idea of an object called a turtle that the user can command about the screen. StarLogo
goes one step further, allowing the user to command thousands of turtles moving on a cellular-automata-like background of
patches. StarLogo is useful for studying the emergent behavior produced by many entities following simple rules. Ant colonies,
traffic jams, forest fires, and bird flocks are among the systems that have been explored using StarLogo.
Stella is a tool for doing systems dynamics modeling (Forrester, 1968). Systems dynamics models are based upon non-linear or
linear differential equations. Feedback is central to many system dynamics models and supplies much of their ability to
surprise their users. Stella is a natural tool for the creation of models that show aggregate behavior. The classic
predator-prey population oscillation model is an example of the sort of dynamic Stella is often used to present.
Greg Kimberly/gregkimb@gak.com