31
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Inspiration

Conway's Game of Life is a well known cellular automaton "played" on an infinite grid, filled with cells that are either alive or dead. Once given an initial state, the board evolves according to rules indefinitely. Those rules are:

  • Any live cell with 2 or 3 living neighbours (the 8 cells immediately around it) lives to the next state
  • Any dead cell with exactly 3 living neighbours becomes a living cell
  • Any other cell becomes a dead cell

Game of Life is known for having simple rules yet structures can quickly become chaotic with minimal change.

Consider the following initial state:

enter image description here

In 5 generations, this reaches this configuration, which is a period 2 oscillator. However, by adding in 8 live cells next to it:

enter image description here

we end up with a completely empty board after 54 generations.


Now, consider instead the following initial state:

enter image description here

That is, CGCC made up of living cells. Each letter is in a \$4\times6\$ bounding box, with a single empty column of cells between boxes, for a total bounding box of \$19\times6\$. This is a zoomed-in version.

After 256 generations, the board looks like

enter image description here

From this point, no meaningful change will happen: there are 2 oscillators which do not interact with anything else, and the rest are still lifes.

Your task is to "destroy" this by adding in living cells around the initial configuration.

You will start with the CGCC initial state, as shown above. You will add \$n\$ living cells to the board. Those cells must be outside of the \$19\times6\$ bounding box of the CGCC (but may touch against the outside). When this new initial state (with your added cells) is run, it must eventually result in an empty board.

Note that the board is considered infinite, so if your configuration produces any spaceships, it is not a valid configuration.

Your score is equal to \$n\$. The lowest score wins, ties are broken by the fewest generations required to empty the board. Please provide either a testing environment to demonstrate your solution, or provide a video/gif of it running.

Here is a pre-filled CGCC pattern in a GoL simulator

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  • \$\begingroup\$ Is there some nice way we could copy the CGCC state into a GoL program, preferably something online? \$\endgroup\$ – xnor Mar 23 at 0:09
  • \$\begingroup\$ @xnor Edited in link \$\endgroup\$ – caird coinheringaahing Mar 23 at 0:17
44
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Score 1, 35 generations

Sorry, but I guess I wrecked the challenge. I brute-forced all meaningful one-dot additions by hand, and found no other answer that wins against this.

Raw ASCII format

 OOO  OOO  OOO  OOO
O    O    O    O
O    O    O    O
O    O OO O    O
O    O  O O    O
 OOO  OO   OOO  OOO

               X

Image of initial state

Copy.sh export

#C Generated by copy.sh/life
x = 19, y = 8, rule = B3/S23
b3o2b3o2b3o2b3o$o4bo4bo4bo$o4bo4bo4bo$o4bob2obo4bo$o4bo2bobo4bo$b3o2b
2o3b3o2b3o$$15bo!

Try this pattern on copy.sh!

Slow animated gif

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4
  • 1
    \$\begingroup\$ Guess I'll have to come up with a version of this that doesn't lend well to brute force! \$\endgroup\$ – caird coinheringaahing Mar 23 at 2:11
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    \$\begingroup\$ @ChartZBelatedly Good luck with that :D \$\endgroup\$ – Bubbler Mar 23 at 2:15
  • 1
    \$\begingroup\$ Can you post a picture of this? I'm unable to recreate it based on the ASCII version. I start with this but it doesn't result in an empty board. \$\endgroup\$ – Engineer Toast Mar 23 at 14:07
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    \$\begingroup\$ @EngineerToast That's weird, it does look identical to my submission. Anyway I included an image and an animated gif into the post. \$\endgroup\$ – Bubbler Mar 23 at 14:19
13
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\$n=2\$, 41 generations

#C Generated by copy.sh/life
x = 19, y = 8, rule = B3/S23
11bo$b3o2b3o2b3o2b3o$o4bo4bo4bo$o4bo4bo4bo$o4bob2obo4bo$o4bo2bobo4bo$b
3o2b2o3b3o2b3o$10bo!

Run it online here. Here's what the initial position looks like:

enter image description here

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  • 1
    \$\begingroup\$ You can make the link work by creating a gist and editing the url from the main post to have a reference to your gist instead of the starting point. \$\endgroup\$ – FryAmTheEggman Mar 23 at 1:45
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    \$\begingroup\$ I suspected an \$n = 2\$ solution was possible, but I'd hoped not. Very nice! \$\endgroup\$ – caird coinheringaahing Mar 23 at 1:48
11
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Score 8, 69 generations

This is what I promised for in the comment, but it got already beaten by Dingus...

I can't upload images right now, so I include a text-based initial configuration and the copy.sh export format.

Raw ASCII format

X                  X
 OOO  OOO  OOO  OOO
O    O    O    O
O    O    O    O
O    O OO O    O
O    O  O O    O
 OOO  OO   OOO  OOO
         X











                          X
                         XX
                         X X

Copy.sh export

#C Generated by copy.sh/life
x = 28, y = 22, rule = B3/S23
o18bo$b3o2b3o2b3o2b3o$o4bo4bo4bo$o4bo4bo4bo$o4bob2obo4bo$o4bo2bobo4bo$
b3o2b2o3b3o2b3o$9bo$$$$$$$$$$$$26bo$25b2o$25bobo!
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    \$\begingroup\$ "69 generations". Nice. \$\endgroup\$ – lyxal Mar 23 at 1:57
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    \$\begingroup\$ I was thinking of a way to change the scoring to at least discourage brute-force solutions. One thought was to make the scoring be [Generation Count] / [Added Cell Count]. However this solution shows that that score can be infinite by moving the attacking glider as far away as you like (with a certain modulus). Back to the drawing board... \$\endgroup\$ – Scott Miller Mar 23 at 13:59
  • 1
    \$\begingroup\$ @ScottMiller well, since lower score is better, you can make it 0 by adding a bunch of random single dots out to infinity \$\endgroup\$ – user253751 Mar 23 at 20:36
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    \$\begingroup\$ If you add a bunch of random dots, you can make it 420, 69 \$\endgroup\$ – user253751 Mar 23 at 21:05

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