This book uses the Stella software to implement system dynamics models, but you can build and test your own models using any of the "stock and flow" programs. This appendix introduces Dynamo, the software originally developed in the 1960s. Jim Lyneis (1994, p. 350) explains that the purpose of Dynamo, from its inception, has been to

support the development and use of system dynamics models for solving real-world business and social problems. Emphasis has been on responding to the consulting and research needs of Pugh-Roberts Associates and the MIT System Dynamics Group. This has led to very powerful software for the creation and analysis of (often) large models. (Lyneis 1994, 350)

Dynamo is described in Forrester's (1961) Industrial Dynamics and in Richardson and Pugh's (1981) System Dynamics Modeling with Dynamo. Concise summaries are appended to books describing major applications of system dynamics, i.e., Meadows' (1974) book on the "WORLD3" model and Lyneis' (1982) book on Corporate Planning and Policy Design. Finally, you may read about Dynamo directly in the users manuals provided by Pugh Roberts Associates, 41 William Linskey Way, Cambridge, MA 02142.

This appendix illustrates Dynamo with simple examples chosen to demonstrate the basic similarity between Dynamo and Stella The examples reveal some differences in terminology and syntax. It is useful to learn the new terms even if you choose to implement your own models in Stella because of the large body of published work in Dynamo.