From Jay Forrester 1971 Book World Dynamics, the earlier, simpler version of the World 3 Limits to Growth Model. adapted from Mark Heffernan's ithink version at Systemswiki.
An element of Perspectives: The Foundation of Understanding and Insights for Effective Action. Register at http://www.systemswiki.org/
Simlation Scenario is below:
Scenario2:Natural resources usage normal 1->0.25
Scenario3:Natural resources usage normal 1->0, Pollution normal 1->0.1 or new natural resources usage 0.25->0