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I'm new to Cellular Automata. I'm looking for examples of Game of Life board states in which only one cell changes in the next generation (to show the effect of the rule that was applied). I'm looking for separate examples for all the 4 rules (as specified on Wikipedia).

The 4 rules are:

  1. Death by underpopulation (less than 2 neighbours)
  2. Survival (2 or 3 neighbours)
  3. Death by overpopulation (more than 3 neighbours)
  4. Reproduction (exactly 3 neighbours)

I have found examples for all the rules except overpopulation. Can you please help?

Edit: Explaination using example from the accepted answer, to explain visually:

I'm looking for a configuration of the board in Conway's Game of Life, where only one cell will die, due to overpopulation (rule 3). So, if this is the current state / configuration of the board:

Overpoplation, before rule is applied

The state of the board will become this, in the next generation:

Overpopluation, after rule has been applied

eMad
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  • Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking. – Community Apr 13 '22 at 12:51

2 Answers2

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Take three horizontal cells, e.g. with coordinates (-1,0), (0,0) and (1,0), and add one cell above the rightmost and one cell below the leftmost: (1,1) and (-1,-1). In this configuration, the central cell will die due to overpopulation, other cells will survive due to having 2 neighbours, and there's no empty spot with exactly 3 neighbours ( 0,1 and 0,-1 each have 4).

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AnatolyVorobey's Z pentomino is probably the indeed the simplest example, as long as you care only about what happens in one time step.

However, if you'd prefer a pattern where one cell dies of overpopulation and all other cells survive forever (and no new cells are born), then adding one live cell to either of the two middle squares of a mirrored dock would work:

Golly screenshot of Conway's Game of Life pattern "mirrored dock" with one extra cell in the middle

When the GoL rule is applied, the extra middle cell will die of overpopulation and all other cells will survive, forming a still life pattern that will remain unchanged by any further applications of the rule.


Edit: Actually, a smaller example can be obtained by adding an extra cell to a krake instead:

Golly screenshot of Conway's Game of Life pattern "krake" with one extra cell in the middle

Again, the middle cell in this pattern will die of overpopulation, while the remaining cells will survive and form a still life.