Random Explorations in Automata Theory Gary J. Shannon Created: Mar. 25, 2003 Last updated: Mar. 25, 2003

Bugs Wars: Part Two

Here's a different kind of bug war.  In this case both species of bug, blue and yellow, live in the same red acid bath. But when the two kinds of bugs both try to gobble up a cell of red acid that cell turns black and becomes useless to both of them. Thus whenever the two kinds of bugs come into contact another cell is blocked off, and gradually a wall begins to form between their two colonies. Both colonies have a "queen bug" that generates the yellow state and the blue state when it touches red, so both will have a good supply of warriors.

Fig. 1. Here contact has just been made and a black
wall has begun to form.

Fig. 2. Now the battle lines have been drawn. Blue is losing
territory to yellow, but is building a strong defensive wall.

Fig. 3. Some time later a dividing wall has been built thick enough that
both kinds of bugs have trouble surviving this no-man's land.

Notice that the wall in figure 3 is not completely solid, but it is dense enough that the bugs have trouble surviving as they try to get through it. There are still occasional skirmishes inside the no-man's land, but both colonies are now safe from large-scale attack from by the other. Blue has given up a lot of territory in the struggle, but at least the colony and the queen bug (state 4) are safe. After figure 3 I let it run for a few hours while I went to a movie. When I came back over 250,000 generations had run and the picture had hardly changed at all! Both colonies were still strong and healthy and the wall was still secure.

Here is the ppr file for this rule:

M,8
1(2)2
2(3)3
3(*)1
2(4,-5)3
0(2,3)1
2(3,1)0
3(2,1)0
3(-2)3
2(5)5
5(*)1
2(6,-3)5
5(-2)5
0(2,5)1
2(5,1)0
5(2,1)0
2(3,5)7
3(7,5)7
5(7,3)7