The cells follow a 7 colour cycle, starting with light green (grass), maturing into forest (dark green) which is burnt to ash (black) where the grass can regrow. The probability of a cell changing colour is controlled using the scrollbars as described in the Instructions section.
| These cells represent the hottest, freshly lit fire. | |
| As the hottest cells cool down they are shown as orange. | |
| And as the orange cells cools further they are shown as red. | |
| Eventually the the fire goes out and only ashes remain. | |
| Fresh shoots growing in the ashes | |
| The fresh shoots grow into luscious vegetation. | |
| Which grows into mature forest. Mature forest can then catch fire re-starting the cycle. Once lightening has set fire to a patch of forest this can spread to adjacent trees. |
The applet simulates the growth of forest and its subsequent destruction by fire. The algorithm uses 8 probabilities, all of which can be adjusted using the scrollbars.
I did have a direct text entry version but none of the browsers I tried it in appeared to support the parsing functions. The probabilities have the following interpretations;
| Cool 1 | The probability that a square currently burning at it's most ferocious (yellow) will cool down to the next hottest square (orange). |
|---|---|
| Cool 2 | The probability that a burning square (orange) will cool even further to the coolest still burning square (red). |
| Cool 3 | The probability that the coolest, still burning square (red) will stop burning and turn to ash (black). |
| Grow 1 | The probability that grass will grow (light green) in a square that is currently ash (black). |
| Grow 2 | The probability that bush and immature trees (green) will grow in a square that is currently grass (light green). |
| Grow 3 | The probability that mature trees (dark green) will grow in a square that is occupied by immature trees (green). |
| Ignite | The probability that a fire (yellow) will start in a square occupied by mature trees (dark green). |
| Spread | The probability that a fire (yellow) will start in mature trees (dark green) adjacent to a square that is already on fire. |