This example is taken from (Smith et al, 2012) who present a simple Bayesian Belief Network with two input nodes for possible changes to cattle subsidy and cattle market price and one output node for number of cattle.
Here are some HUGIN widgets for interacting with the model shown on the right (click on the probability bar to instantiate a node or remove evidence):
As an example, if the subsidies and market prices are not changed, there is a 90 percent chance the cattle number will remain within the same class.
Smith, R., Dick, J., Trench, H., and van Oijen, M. (2012). "Extending a Bayesian Belief Network for ecosystem evaluation". In: 2012 Berlin Conference of the Human Dimensions of Global Environmental Change on "Evidence for Sustainable Development", Berlin, Germany, 5-6 October 2012.