1. In extension 1 of the Fire Simple model, there are two parameters governed by sliders, DENSITY and PROBABILITY-OF-SPREAD. How do these two interact with regard to a critical spread of the fire?
2. The original Fire Simple model has each patch check its four neighbors in the cardinal directions. Modify it so that it checks all eight of its Moore neighbors. How does this affect the spread of the fire? Is there still a critical density for the forest fire spread? If so, what is it?