The example is based on Jay Forrester's World Dynamics model as published in the book World Dynamics (available from Productivity Press). The World model has been modified to remove the various switch times and alternate parameters. This was done in order to make it simpler to present this Venapp.
Two gaming variables were also added to this model.
capital investment rate normal= GAME (capital investment rate normal c)
natural resource utilization normal= GAME (natural resource utilization normal c)
Here the same names ending in c represent constants in the model. We chose to have people game on the investment rate rather than the actual amount of investment being made because it would be hard to most people to get a sensible order of magnitude value for investment in this model. For applications that are closer to people's every day experience, or settings where some amount of preparation is expected before playing a game using variables like actual investment would be more appropriate (that is we could use an equation like (capital investment = GAME( Population * capital investment multiplier * capital investment rate normal)).