This program models two-dimensional cellular automata. A cellular automaton is a computational machine that performs actions based on certain rules. It can be thought of as a board which is divided into cells (such as square cells of a checkerboard). Each cell can be either on or off. This is called the "state" of the cell. According to specified rules, each cell will be on (alive) or off (dead) at the next time step. In this case of two-dimensional cellular automata, each cell checks the state of itself and its eight surrounding neighbors. and then sets itself to either on or off, depending upon the rule. The rule is as follows: If there are less than two "on" neighbors, then the cell turns off. If there are more than three "on" neighbors, the cell turns off. If there are 2 "on" neighbors, the cell remains in the state it is in. If there are exactly three "on" neighbors, the cell turns on This is done in parallel and continues forever. Cellular automata can be created on any board size and dimension. As explained above, Life is a cellular automaton that simulates the growth, life and death of "organisms". Their growth, life or death depends upon the amount of their neighbors. There are certain recurring shapes in this simulation, one of which is the glider. The glider is composed of 5 cells which form a small arrow-headed shape. This glider will "float" across the screen, retaining its shape. The glider gun is a large conglomeration of cells that repeatedly spits out gliders. A blinker is a block of 3 cells (either up and down or left and right) that rotates between horizontal and vertical orientations.
For detailed instructions on using the program, take a look at the info window from the Life model.
Click on one of the pictures to see a quicktime movie of the model: