This package contains two directories: world-dynamics and world3.
The first directory, world-dynamics, contains an implementation of Jay Wright Forrester's World Dynamics model in C++ and Javascript. The Javascript version can be embedded in a web page and you can find an example of that, too. Check the index.html page.
The second directory, world3, contains the start of an implementation of the World3 model that was used by the Club of Rome and described in the book Limits to Growth. The code is unfinished.