### About this model

Each cell in this model is one of three states: burnable-green (0),
burning-red (1) or burned-black (2). If a burnable cell has a burning
neighbor, it will become burning in the next generation with the
probability given by the slider's value. Each burning cell burns for
exactly 1 generation, and then changes to burned. Each cell can also
be part of a firewall (state 3). Firewalls (blue) remain in a fixed
state and can prevent fires from spreading.

The initial configuration can be altered by left-clicking on a
cell to change its color and dragging that cell to change the colors
of neighboring cells.