Thread for basic questions

[Koiti Kimura]

Does a 3D or 4D or arbitrary multi-D Life have glider guns?
Did Prof. Bays find ones in 3D Life?

[Saka]

Where can I find full/partial lists of still lives by cell count? Perhaps a more complete one than on the wiki?

Code: Select all

x = 13, y = 8, rule = B3/S23
2o$bo9b2o$o6bo3bo$2o5b3obo$2bo7bo$2obo3b3o$o2bo3bo$b2o!

[gameoflifemaniac]

Where can I find full/partial lists of still lives by cell count? Perhaps a more complete one than on the wiki?

Code: Select all

x = 13, y = 8, rule = B3/S23
2o$bo9b2o$o6bo3bo$2o5b3obo$2bo7bo$2obo3b3o$o2bo3bo$b2o!

You're lucky.
See my posts in wwei23's still life thread. There there are all still lifes up to 13 bits (I'm working on the 14-bit). And then there are 16, 17 and 18-bit still lifes, which I copied in groups of thousands from Mark Niemiec's Life Page.
YOU ARE REALLY LUCKY

[Apple Bottom]

Where can I find full/partial lists of still lives by cell count? Perhaps a more complete one than on the wiki?

Mark Niemiec's site
Heinrich Koenig's site

[Macbi]

Has anyone tried looking at B3/S23 in the 4D vN neighbourhood?

[praosylen]

Has anyone tried looking at B3/S23 in the 4D vN neighbourhood?

I'm not sure, but it's probably not that interesting: no pattern can escape its initial bounding box without B0 or B1. It might be approximately equivalent in dynamics to B5/S12 or something similar in the 2D Moore neighborhood, which is to say, not very interesting.

[Macbi]

Has anyone tried looking at B3/S23 in the 4D vN neighbourhood?

I'm not sure, but it's probably not that interesting: no pattern can escape its initial bounding box without B0 or B1. It might be approximately equivalent in dynamics to B5/S12 or something similar in the 2D Moore neighborhood, which is to say, not very interesting.

Good point. So in vN every rule is either explosive or bounded? That's kind of boring.

[Naszvadi]

Has anyone tried looking at B3/S23 in the 4D vN neighbourhood?

I'm not sure, but it's probably not that interesting: no pattern can escape its initial bounding box without B0 or B1. It might be approximately equivalent in dynamics to B5/S12 or something similar in the 2D Moore neighborhood, which is to say, not very interesting.

Good point. So in vN every rule is either explosive or bounded? That's kind of boring.

Nope, see this:

Code: Select all

x = 0, y = 0, rule = B02/S1V
o$b2o$bobo$3bo16$2o2$bobo$2b2o16$2o$2bo$b2o$3bo16$2o$obo2$2b2o16$4o$o2bo$o2bo$4o!

Well, any neighbourhoods other than Neumann ones are asymmetrical. This means that the neighbourhood graphs are not edge-transitive. Not so many related grids exist in higher dimensional euclydean spaces, and even finite many exist in lower dimensions AFAIK, but I might be wrong due to my possible false memory.

And there are even hexagonal _outer-totalistic_ b0-less rules with gliders.

Simplectic grids is an undiscovered area, today I did some related posts.

[Saka]

can someone send me a link to bellman-win and the instructions? I can't seem to find it.

[Saka]

can someone send me a link to bellman-win and the instructions? I can't seem to find it.

Hello?

[Apple Bottom]

Hello?

https://github.com/simsim314/BellmanWin (includes binaries)
viewtopic.php?p=13784#p13784 (older compiled version on the forums)
viewtopic.php?f=9&t=1139 (Bellman thread)

[drc]

What would it take to run a search where a glider hits 2-5 still lifes (with honey farms and fleets and bakeries, and 3/4 honey farms and 1/2 honey farms as well. No oscillators) and releases a glider and makes the debris reform but moved a bit? Kind of like HBK. Then they could be rubbed together to produce more gliders or xwsses

[BlinkerSpawn]

What would it take to run a search where a glider hits 2-5 still lifes (with honey farms and fleets and bakeries, and 3/4 honey farms and 1/2 honey farms as well. No oscillators) and releases a glider and makes the debris reform but moved a bit? Kind of like HBK. Then they could be rubbed together to produce more gliders or xwsses

I feel like a similar search was done some months ago.

[dvgrn]

What would it take to run a search where a glider hits 2-5 still lifes (with honey farms and fleets and bakeries, and 3/4 honey farms and 1/2 honey farms as well. No oscillators) and releases a glider and makes the debris reform but moved a bit? Kind of like HBK. Then they could be rubbed together to produce more gliders or xwsses

Ethanagor brought up an idea along those lines, back in July (and you responded with the half-bakery reaction). As gmc_nxtman mentioned then, Gabriel Nivasch wrote a search utility, sngdetect, that hunted through a fairly large space but didn't find anything clean. There were a number of two-object constellations that re-formed exactly, but they always came along with lots of extra junk, and so nobody has quite been able to figure out how to use them for anything. I think this was the cleanest by far of the new re-creations that were found by that search:

Code: Select all

#C Gabriel Nivasch, 17 Mar 2000
x = 75, y = 76, rule = B3/S23
o$b2o$2o20$23bo$24b2o$23b2o20$46bo$47b2o$46b2o20$69bo3b2o$70b2ob2o$69b
2o5$68b2o$67bo2bo$68b2o!

-- Interesting, right? But where exactly do you get a stream of gliders with 1hd offset like that?

A sngdetect-type search could certainly be re-run now with more objects in the constellations, but it's a big undertaking -- the search would have to be run for months, probably, and still might not find anything. Then again, it might!

See also Alan Hensel's Fluff Relays thread from 2013. The last post was from me, with a hare-brained idea that restricting the constellations to just arrangements of blocks might possibly be a good way of reaching out into some unexplored corners of search space, with some vague chance of turning up something interesting -- at least maybe something new along the lines of the old result that dbell just posted.

Paul Chapman started running a similar search for a Spartan stable reflector, I think somewhat along the lines of simsim314's CatForce, several years ago -- just a few months or a year A.G., I think (After Gemini). There was also some experimentation with the idea that the mechanism might take several cycles to return exactly to its starting configuration -- the first reflection might throw off a block, for example, which the second reflection would consume. Or the constellation might send successive gliders in alternate directions and then recover, or it might move a little as you suggest... lots of things to look for.

Then the Snark showed up, but a Spartan junk-constellation reflector never did. Negative results are never as exciting to report as positive ones... and it's hard to do this kind of search thoroughly with more than three or four objects or a very constricted area, so it's hard to even report a definitive negative result.

[Macbi]

Is it known what the smallest still life is that can't be deleted by a single glider?

[toroidalet]

Is it known what the smallest still life is that can't be deleted by a single glider?

I think that it's long ship:

Code: Select all

x = 421, y = 57, rule = B3/S23
132bo31bo30bo34bo30bo16bo28bo42bo30bo$133bo31bo30bo34bo30bo16bo28bo42b
o30bo$131b3o29b3o28b3o32b3o28b3o14b3o26b3o40b3o28b3o9$144b2o29b2o28b2o
32b2o28b2o14b2o26b2o40b2o28b2o$144bobo28bobo27bobo31bobo27bobo13bobo
25bobo39bobo27bobo$145bobo28bobo27bobo31bobo27bobo13bobo25bobo39bobo
27bobo$146b2o29b2o28b2o32b2o28b2o14b2o26b2o40b2o28b2o15$385bo24bo$bo
21bo42bo22bo18bo23bo23bo47bo44bo56bo79bo24bo$2bo21bo42bo22bo18bo23bo
23bo47bo44bo56bo76b3o22b3o$3o19b3o40b3o20b3o16b3o21b3o21b3o45b3o42b3o
54b3o8$395b2o22b2o$20b2o19b2o40b2o20b2o16b2o21b2o21b2o45b2o44b2o54b2o
74bobo21bobo$19bobo18bobo39bobo19bobo15bobo20bobo20bobo44bobo43bobo53b
obo30bo42bobo21bobo$18bobo18bobo39bobo19bobo15bobo20bobo20bobo44bobo
43bobo53bobo32bo41b2o22b2o$18b2o19b2o40b2o20b2o16b2o21b2o21b2o45b2o44b
2o54b2o31b3o9$361b2o$360bobo$359bobo$359b2o!

Some collisions aren't shown due to the symmetry of the long ship.

[Macbi]

Is it known what the smallest still life is that can't be deleted by a single glider?

I think that it's long ship:

Code: Select all

x = 421, y = 57, rule = B3/S23
132bo31bo30bo34bo30bo16bo28bo42bo30bo$133bo31bo30bo34bo30bo16bo28bo42b
o30bo$131b3o29b3o28b3o32b3o28b3o14b3o26b3o40b3o28b3o9$144b2o29b2o28b2o
32b2o28b2o14b2o26b2o40b2o28b2o$144bobo28bobo27bobo31bobo27bobo13bobo
25bobo39bobo27bobo$145bobo28bobo27bobo31bobo27bobo13bobo25bobo39bobo
27bobo$146b2o29b2o28b2o32b2o28b2o14b2o26b2o40b2o28b2o15$385bo24bo$bo
21bo42bo22bo18bo23bo23bo47bo44bo56bo79bo24bo$2bo21bo42bo22bo18bo23bo
23bo47bo44bo56bo76b3o22b3o$3o19b3o40b3o20b3o16b3o21b3o21b3o45b3o42b3o
54b3o8$395b2o22b2o$20b2o19b2o40b2o20b2o16b2o21b2o21b2o45b2o44b2o54b2o
74bobo21bobo$19bobo18bobo39bobo19bobo15bobo20bobo20bobo44bobo43bobo53b
obo30bo42bobo21bobo$18bobo18bobo39bobo19bobo15bobo20bobo20bobo44bobo
43bobo53bobo32bo41b2o22b2o$18b2o19b2o40b2o20b2o16b2o21b2o21b2o45b2o44b
2o54b2o31b3o9$361b2o$360bobo$359bobo$359b2o!

Some collisions aren't shown due to the symmetry of the long ship.

Thanks! Maybe I could have guessed that: its large amount of symmetries means that it has fewer possible collisions that might delete it.

[dvgrn]

Is it known what the smallest still life is that can't be deleted by a single glider?

I think that it's long ship...

Thanks! Maybe I could have guessed that: its large amount of symmetries means that it has fewer possible collisions that might delete it.

Interesting -- long ship wasn't on my mental list of common still lifes that can act as one-time turners, in this case a clean 180-degree output. Different output lane relative to the input from the long boat one-time turner, but it converges to the exact same mechanism:

Code: Select all

x = 31, y = 9, rule = LifeHistory
.C18.C$2.C18.C$3C16.3C2$29.2C$10.2C16.C.C$9.C.C15.C.C$8.C.C17.C$8.2C!
#C [[ AUTOSTART PAUSE 2 GPS 10 THUMBNAIL THUMBSIZE 2 STOP 59 ]]

I guess long ship isn't in the top 20 most common still lifes, so maybe it doesn't quite count as common -- but it's in the top 25.

[gameoflifemaniac]

Is there any one-time reflector synthesizable by 2 gliders that reflects by 180 degrees?

[dvgrn]

Is there any one-time reflector synthesizable by 2 gliders that reflects by 180 degrees?

Nothing comes to mind, no, not if you want a clean one-time 180-degree turner... except that two gliders can make one glider (with a kickback reaction), and then that one glider can reflect another glider 180 degrees, two different ways (90- and 180-degree collision). But that's clearly cheating.

If you allow p2 constellations as turners, you can get close:

Code: Select all

x = 8, y = 12, rule = B3/S23
o$o$o$5b2o$4bo2bo$4bobo$5bo3$5b3o$7bo$6bo!

(and if that's any use, I seem to recall you can get a wing out of a collision with some stable object or three also, maybe a 2-glider-constructible one)

... along with other weird things that nobody has ever quite found a use for:

Code: Select all

x = 10, y = 12, rule = B3/S23
2bo$2bo$2bo$7b2o$6bo2bo$6bobo$7bo3$3o$2bo$bo!

By now a thorough exploration has been done of all the small 2-glider constellations plus one glider, no doubt several times, most recently by 2718281828 -- but I don't know if there were any lucky clean 180-degree turner reactions among them.

[Saka]

What is the highest possible density change in 1 generation of a pattern in Life? And are there any examples of it?

[Cclee]

I believe it would be very close to 100% but not there because of arbitrarily extendable patterns that die and have a high density. However I can’t remember the set of patterns offhand.

Edit: wait by you mean highest density change by bounding box? Because if so it is just a domino spark, which goes from full density to empty in its 2x1 bounding box in one gen

[Macbi]

What is the highest possible density change in 1 generation of a pattern in Life? And are there any examples of it?

I was thinking about this the other day.
Density decrease can be arbitrary: huge solid blocks disappear.
Density can't increase by more than a factor of 3: each old alive cell can remain alive by touching 2 cells, and contribute 1 of the 3 required parents of its six dead neighbours. 1 + 6*1/3 = 3. I don't know if this can be achieved exactly, but a long line of live cells comes arbitrarily close.

I wonder what the best density increase in two steps is? Off the top of my head I can't even get a factor better than 3.

[gameoflifemaniac]

How does the apgcode syntax code work?

[drc]

How does the apgcode syntax code work?

apgcode
Alternatively yl111_2_3_444 are encoded so that:
111 is the amount of generations for the population plot to repeat, that's why there are yl1's in some non-b2a rules.
2 has something to do with the period of the ash
3 is the population of the ash, I don't know if it's optimized to be the smallest possible, it seems to be huge in the presence of rakes.
444 is the hash of the entire thing.