Thread for basic questions

[hotdogPi]

I actually would say it doesn't need to be random. If I draw a scribble, and it produces a rare object, it would typically be considered natural. (An exception is e.g. if a bi-pentadecathlon is formed due to a long horizontal line in the scribble.)

Similarly, my oscillator partials RLE breaks down and forms some ash (since they're all partials). A BTS is likely not natural, as it was there from the beginning and survived. Same with pretty much any oscillator of period 4 or greater. But if a fourteener or a switch engine forms, it's probably natural, since it got no help from the initial state.

[dvgrn]

I actually would say it doesn't need to be random. If I draw a scribble, and it produces a rare object, it would typically be considered natural. (An exception is e.g. if a bi-pentadecathlon is formed due to a long horizontal line in the scribble.)

Similarly, my oscillator partials RLE breaks down and forms some ash (since they're all partials). A BTS is likely not natural, as it was there from the beginning and survived. Same with pretty much any oscillator of period 4 or greater. But if a fourteener or a switch engine forms, it's probably natural, since it got no help from the initial state.

That's certainly a good informal summary of the idea of "natural". But in practice, these days, "natural" and "semi-natural" mostly get applied to objects that appear in soups generated via SHA-256 or similar methods -- i.e., where no way is known to reverse-engineer or design the position of bits in the image.

As soon as you relax this requirement and allow a claim of "natural" for an object that evolves from a random scribble, it becomes impossible to know if something is "really natural" or not. It's quite easy to make starting patterns that are indistinguishable from random scribbles, or indistinguishable from random 16x16 soups, that nonetheless produce objects that have not yet appeared naturally.

For example, if you just inspected this 16x16 pattern posted in the Trolls thread and didn't look at anything else on the page, how would you know whether this was an "engineered with LLS" vs. a "natural" appearance of a loafer?

[GUYTU6J]

How to complete the following xs16_0o8bbgzc8421 synthesis?

Code: Select all

x = 21, y = 9, rule = B3/S23
8b3o$9bo8b2o$b2o6bo8bobo$b2o5bobo8bo$7b2ob2o$8bobo$9bo2$3o!

The central region refuses to be identified by synthesise-patt.py, octohash and spark-search. I want to try popseq.c but am unsure how it works as the relevant Tutorials part is not clear enough; apparently the original package does not contain any 4G collision database. Do I just compile it, feed it with the active pattern, and wait while the script automatically enumerates and tries all 4G collisions in situ?

EDIT after seeing the reply below: thank you for the explanation as well as the solution. The complete synthesis takes 11G:

Code: Select all

x = 171, y = 25, rule = B3/S23
162bo$163bo$161b3o$106bo$106bobo$106b2o58b2o$166b2o$11bobo88bobo$12b2o
88b2o$12bo90bo61b2o$107b2o56bobo$2o88b2o15bobo58bo$2o88b2o16bo60bo$
166bo3bo$22b2o80bo61b4o$22bobo78b2o$o21bo67bo12bobo62b2o$o89bo77b2o$o
89bo4b3o$97bo$96bo2$73b2o$74b2o$73bo!

[Goldtiger997]

I want to try popseq.c but am unsure how it works as the relevant Tutorials part is not clear enough; apparently the original package does not contain any 4G collision database. Do I just compile it, feed it with the active pattern, and wait while the script automatically enumerates and tries all 4G collisions in situ?

Yep, you are correct about how you use popseq. I think chris_c's original popseq post explains it pretty well.

However, in this specific case, I recommend using something else than popseq. That difficult region evolves into the 2-blinker constellation 3o3b3o!, so you can use wildmyron's version of synthesise-constellation.py, which I think contains all of the collisions that popseq uses and more! Futhermore, wildmyron's script runs almost instantly, unlike popseq. For these reasons, I recommend using synthesise-constellation-4G if possible, which typically means that the region you are trying to synthesise produces a small to medium size constellation that contains no escaping gliders, and also is not very common.

When I run synthesise-constellation-4G.py on the aforementioned 2-blinker constellation, I get this output:

Code: Select all

x = 924, y = 723, rule = B3/S23
20bobo$20b2o$21bo4$719bo$610bobo105bo$109bo307bo193b2o105b3o188bo$107b
obo307bobo85bobo103bo295bobo$108b2o97bobo97bobo107b2o87b2o7bo292bobo4b
o92b2o$208b2o98b2o196bo8bobo291b2o4bobo$111b2o95bo7bo91bo206b2o93bobo
196bo5b2o99bo$111bobo101bo196bo198b2o303bobo$111bo103b3o97b3o94bobo
196bo304b2o$210b2o98b2o3bo92bo3b2o103b3o186bo103b2o101bo$209b2o98b2o5b
o92bo107bo95bo93b2o100b2o101b2o$115b3o93bo99bo95b3o108bo94bobo90b2o
103bo100bobo$115bo497b2o95b3o$116bo595bo$711bo2$10bo$4bobo2bo$5b2o2b3o
$5bo79$322bo$222bo98bo100bo99bo202bo$222bobo96b3o98bobo96bo99bo101b2o
95bobo$8bo213b2o198b2o97b3o97bobo100b2o94b2o98bo$9bo611b2o198bo98bobo$
7b3o99bo192bo100bo99bo99bo95bobo102bo115b2o$110bo7bo83bo100b2o99b2o98b
2o98b2o94b2o103b2o99bo$12bo95b3o5b2o85b2o97b2o99b2o98b2o98b2o95bo103b
2o98bobo$10b2o105b2o83b2o701b2o$11b2o99bo$111bo$111b3o699bobo$17b3o
290bobo98bobo97bobo97bobo199b2o94bo3bobo$17bo192bobo97b2o99b2o98b2o98b
2o95bobo97bobo3bo95bo2b2o$18bo191b2o93bobo3bo94bobo3bo93bobo3bo93bobo
3bo96b2o2bobo93b2o97b3o3bo$205bobo3bo94b2o99b2o98b2o98b2o100bo3b2o94bo
$206b2o98bo100bo99bo99bo106bo$206bo84$obo219bo299bo198bo$b2o116bobo99b
o100bobo97bo97b2o98bo99bo100bobo97bo$bo117b2o100b3o98b2o98bobo96b2o96b
o100b3o98b2o98bobo$23bo96bo82bo99bo19bo80bo17b2o78bobo114b3o82bo99bo
17bo82bo15b2o$22bo178bobo100b2o99bo97b2o197bobo100b2o99bo$22b3o81bo95b
2o99b2o98b3o97bo199b2o99b2o98b3o$104bobo498bo$105b2o499b2o$605b2o$513b
o95bobo101bo100bo99bo$213bo100bo99bo97bo97b2o100bo100bo99bo$109bo3bobo
96bo100bo99bo98b3o95bo3bobo95b3o98b3o97b3o$8bobo99bo2b2o97b3o98b3o97b
3o93bo104b2o93bo100bo99bo$9b2o97b3o3bo94bo100bo99bo96bobo105bo91bobo
98bobo97bobo$9bo3bobo191bobo98bobo97bobo97b2o198b2o99b2o98b2o$13b2o
193b2o99b2o98b2o$14bo85$21bo198bo101bo297bo98bo$19b2o96bobo99bo85bo14b
2o98bobo97bo97b2o98bo100bobo97bo$20b2o95b2o100b3o81bobo15b2o97b2o98bob
o96b2o97b3o98b2o98bobo$3bobo112bo86bo98b2o99bo15bo84bo13b2o82bobo99bo
99bo13bo86bo11b2o$4b2o197bobo200b2o99bo97b2o97bobo100b2o99bo$4bo104bo
94b2o199b2o98b3o97bo99b2o99b2o98b3o$110bo$108b3o502bo99bo100bo99bo$13b
o199bo200bo99bo97bo99bo100bo99bo$12bo100bobo96bo94bobo103bo99bo98b3o
97b3o98b3o97b3o$12b3o98b2o97b3o93b2o103b3o97b3o93bo99bo100bo99bo$9bo
98bobo3bo94bo98bo3bobo95bo99bo96bobo97bobo98bobo97bobo$7bobo99b2o96bob
o102b2o94bobo97bobo97b2o98b2o99b2o98b2o$8b2o99bo98b2o103bo95b2o98b2o
86$404bo16bo$405bo14bo99bo98bo$19bo98bo284b3o14b3o97bobo96bobo185bo
100bo$17b2o98bo100bobo97bo187bo13b2o97b2o87bo99bo100bo8bo$18b2o97b3o
98b2o98bobo186bo96bobo99bobo97b3o10bo87b3o6b2o$5bobo99bo99bo11bo88bo9b
2o185b3o97b2o100b2o9bobo96b2o98b2o$6b2o97bobo100b2o99bo295bo112b2o98b
2o$6bo99b2o99b2o98b3o409bo$13bo99bo100bo99bo$12bo99bo100bo99bo595bo3bo
bo$12b3o97b3o98b3o97b3o397bobo91bobo2bobo95bo2b2o$9bo99bo100bo99bo96bo
bo298bobo2b2o93b2o2b2o94b3o3bo$7bobo97bobo98bobo97bobo97b2o2bobo92bobo
3bo92bobo3bo96b2o3bo93bo4bo$8b2o98b2o99b2o98b2o97bo3b2o94b2o2bo94b2o2b
o97bo$413bo94bo3b3o92bo3b3o83$602bo$504bo95bobo$4bobo495bobo96b2o$5b2o
97bo398b2o300bo$5bo99b2o14bo85bo200bo296bo100bo97bobo$104b2o14bo87b2o
96bobo100b2o295bo97b3o98b2o$120b3o84b2o98b2o8bo90b2o294b3o198bo$307bo
9bobo97bo93bo201bo$219bo97b2o98bobo86bo3b2o200b2o$217b2o198b2o87b2o2bo
bo195bo3bobo$19bo198b2o285bobo99b3o3bo94b2o$19bobo587bo2b2o93bobo99bo
3b3o92b3o3bo$19b2o192bobo191bobo198bo3bobo194b2o2bo96bo2b2o$213b2o91bo
bo3bo95b2o398bobo3bo94bo3bobo$208bobo3bo92b2o2bo96bo3bobo$9bobo95bobo
99b2o96bo3b3o98b2o306b2o$10b2o96b2o2bobo94bo203bo305b2o$10bo3bobo91bo
3b2o607bo98b2o96b3o$14b2o97bo408bo296b2o97bo$15bo505b2o298bo97bo$521bo
bo$623b2o$622b2o$624bo78$303bo199bo$304bo98bo100bo99bo$302b3o96bobo98b
3o97bobo$107bo294b2o199b2o200bo$7bo100bo96bobo495bobo97bobo$8bo97b3o5b
o91b2o496b2o98b2o100bo$6b3o103b2o92bo497bo199bobo12bobo$113b2o95bo498b
o195b2o12b2o$15bo194bobo494b2o211bo$10bo3b2o194b2o306bo99bo89b2o$10b2o
2bobo95b2o205bo98bo97b2o98b2o197bo$9bobo100bobo202b2o97b2o99b2o98b2o
194b2o101bo$18b2o92bo98b2o105b2o97b2o290b2o103b2o95b3obo$18bobo99bo89b
2o496b2o203bob3o$18bo100b2o91bo302b2o98b2o93bo110bo90bo$119bobo96b2o
96b2o97b2o97b2o98b2o103b3o91b2o5b2o$217b2o96b2o97b2o100bo99bo102bo92b
2o6bobo$219bo97bo98bo104b3o97b3o96bo93bo$322b3o96b3o97bo99bo$322bo98bo
100bo99bo$323bo98bo82$11bobo$11b2o$5bo6bo105bobo97bo$3bobo112b2o88bo7b
2o$4b2o113bo86bobo8b2o$107bo99b2o$105bobo$6b2o98b2o$5b2o$7bo$217bo$
115bo96b3obo$110b3obo99bob3o$112bob3o96bo$111bo$19b3o$19bo$20bo!

As you can see, there are many different reactions that produce the constellation, and we are looking for a specific one. Fortunately the reaction we're looking for is long lasting and symmetrical, making it quite distinctive. So it isn't too hard to find it in the leftmost column of the second last row (changing to LifeHistory can be helpful for this process). Thus, we get the following incomplete synthesis:

Code: Select all

x = 22, y = 25, rule = B3/S23
20bo$19bo$19b3o2$17bo$15b2o$16b2o5$17b2o$2o15bobo$2o16bo4$o$o$o16b2o$
16b2o$18bo$2b2o$bobo$3bo!

[dvgrn]

For these reasons, I recommend using synthesise-constellation-4G if possible, which typically means that the region you are trying to synthesise produces a small to medium size constellation that contains no escaping gliders, and also is not very common.

Thanks, that's a good reminder -- I don't always think of the right trick to use. On the other hand, for many of these cases it's pretty annoying to have to scan through hundreds of constellation matches to find the rare ones that make the right predecessor -- especially when the reaction envelope isn't particularly recognizable, so the LifeHistory trick doesn't help.

So... what should we write as a post-processor or variant of wildmyron's script, to automatically run some kind of configurable test on each possible result, and only print the ones that match? This would be very easy Python, and would still run almost instantly -- kind of the best of all possible worlds.

[Herschel of Ostropol]

Are there any spaceships besides the glider that have a constant number of live cells?

[Sokwe]

Are there any spaceships besides the glider that have a constant number of live cells?

25P3H1V0.1 has a constant population of 25. I'm sure there are other small examples, but I don't know them off-hand.

[hotdogPi]

Several flotillas, like this one with 26:

Code: Select all

x = 11, y = 6, rule = B3/S23
b2o4bobo$3o3bo3bo$3o7bo$2obo6bo$b3o3bo2bo$2bo5b3o!

[Qyz]

May there be "indestructible" objects? that is, an object that can be caught up by common patterns (say, xWSS and gliders) but cannot be destructed completely?
Objects like c/2o, c/4d spaceships are excluded because they cannot be caught up, but some c/2o puffers can be included because signals may pass faster using the debris.


The rule could be:
We first fix a number N(say, 100)
We are alowed to place common(more generally, constructible) objects in |x|<N, |y|<N at any time.
At t=0, there is a pattern(spaceship or puffer) somewhere far from the origin.

If we can destruct the object wherever it is, we call it destructible.

(For example, a 3c/7o spaceship is very likely to be desturctible, because we may prepare a LWSS to hit the spaceship, and more to stop the gliders produced.)

Something that I haven't get:

(1) Are all still lifes/constellations destructible?
(2) Are all slow(slower than (m,n)/(2m+2n)) spaceships destructible?
(2a) Can we always reach the spaceship? It takes time to push the target block in normal construction. For example, how to reach a (11,2)/27 pattern?
(2b) Similar to (1),but also is there enough time to make objects stop the gliders produced and clear the debris (as the target place changes)?

(3) Can a (m,n)/(2m+2n) puffer be determined destructible or not? For example, Hivenudger 2? None of the three standard Blinker fuses works. Looks like it has a self-protecting mechanism.

(ex) Also there is another question, for (m,n)/(2m+2n) spaceships that will get out of control soon. (For example, a Sir Robin at (2000,2000) in (-2,1)/6 direction, it will reach (0,3000) in 6000 generations, so we must emit spaceships to stop it soon, and might have no time to prepare for the possible gliders in the debris.)

These are some of my questions about the thread How usable is the reverse caber tosser?.

[mniemiec]

May there be "indestructible" objects? ...

It depends a lot on what exactly you mean by "destructible" in this context. If it means "totally eliminated, resulting in an empty field" when hit by a single glider or XWSS, this is likely true for many objects, as the likelihood of surviving destruction increasing with N. If it means "damaged so that it no longer functions the way it usually does", it's unlikely that patterns immune to such damage exist in Life (but they do in some other rules). There are many objects that cannot be totally eliminated by a single glider/XWSS, but can be when hit by several of them, either simultaneously, or one at a time.

[dvgrn]

The rule could be:
We first fix a number N(say, 100)
We are alowed to place common(more generally, constructible) objects in |x|<N, |y|<N at any time.
At t=0, there is a pattern(spaceship or puffer) somewhere far from the origin.

Depending on where "far from the origin" is exactly, this definition allows even things like c/2 spaceships to be caught up with sometimes.

For your N=100 case, for example, if you put the following constuctible objects inside |x|<N, |y|<N, then an MWSS can be well outside that area and running away as fast as it can, and it will still get caught... very messily:

Code: Select all

x = 201, y = 221, rule = LifeSuper
98.3A$98.A2.A$98.A$98.A3.A$98.A$99.A.A16$200N$N198.N$N198.N$N.A194.A.
N$NA.A192.A.AN$N.A194.A.N$N198.N$N.A194.A.N$NA.A192.A.AN$N.A194.A.N$N
198.N$N.A194.A.N$NA.A192.A.AN$N.A194.A.N$N198.N$N.A194.A.N$NA.A192.A.
AN$N.A194.A.N$N198.N$N.A194.A.N$NA.A192.A.AN$N.A194.A.N$N198.N$N.A
194.A.N$NA.A192.A.AN$N.A194.A.N$N198.N$N.A194.A.N$NA.A192.A.AN$N.A
194.A.N$N198.N$N.A194.A.N$NA.A192.A.AN$N.A194.A.N$N198.N$N.A194.A.N$N
A.A192.A.AN$N.A194.A.N$N198.N$N.A194.A.N$NA.A192.A.AN$N.A194.A.N$N
198.N$N.A194.A.N$NA.A192.A.AN$N.A194.A.N$N198.N$N.A194.A.N$NA.A192.A.
AN$N.A194.A.N$N198.N$N.A194.A.N$NA.A192.A.AN$N.A194.A.N$N198.N$N.A
194.A.N$NA.A192.A.AN$N.A194.A.N$N198.N$N.A4.A4.A4.A4.A4.A4.A4.A4.A4.A
4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A
4.A4.A4.A4.A4.A4.A4.A.N$NA.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A
2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.
A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A
.A2.A.A2.A.A2.A.AN$NA.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A
2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.
A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A.A2.A
.A2.A.A2.A.AN$N.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A
4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A.N$
N198.N$N198.N$N.3A2.3A2.3A2.3A2.3A2.3A2.3A2.3A2.3A2.3A2.3A2.3A2.3A2.
3A2.3A2.3A2.3A2.3A2.3A2.3A2.3A2.3A2.3A2.3A2.3A2.3A2.3A2.3A2.3A2.3A2.
3A2.3A2.3A2.3A2.3A2.3A2.3A2.3A2.3A4.N$N3.A4.A4.A4.A4.A4.A4.A4.A4.A4.A
4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A
4.A4.A4.A4.A4.A4.A4.N$N2.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A
4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A4.A
4.A5.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N
$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.
N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N
198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$
N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N
$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.
N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N
198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$
N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N
$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.
N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N
198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$
N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N$N198.N
$N198.N$N198.N$N198.N$N198.N$N198.N$201N!
#C [[ TRACK 0 -1/2 ]]

See also this post by Extrementhusiast for a solution to the problem of allowing c/2 spaceships to pass through an area, and then still have time to use gliders to build something like the above that can still catch up to them from behind.

[Wyirm]

Are oscillators considered spaceships with displacement 0,0? Does this make any periodic object a spaceship?

[dvgrn]

Are oscillators considered spaceships with displacement 0,0? Does this make any periodic object a spaceship?

Nope -- a spaceship is a "finite pattern that returns to its initial state after a number of generations (known as its period) but in a different location."

That last phrase was probably put in there specifically to thwart people who are unreasonably fond of having one thing be a degenerate instance of another. Speed-0 spaceships would just be a downhill step toward "stable speed-0 spaceships" such as blocks, and there's just no reason to go there.

It would be like insisting on always calling line segments "0-degree triangles" -- you don't get any use out of the "triangle" part of the definition at all, so there's really not a lot of point (heh) in using the word.

[AlbertArmStain]

Is there a smaller form for this?

Code: Select all

x = 38, y = 22, rule = B3/S23
2o$2o7$21b2o$20b2o$15b2o5bo$14b2o$16bo6$22b3o$22bo12b2o$23bo11bobo$35b
o!

I can't seem to find anything smaller.
EDIT:
The block doesn't have to be in the same lane, however, the still life has to be a block.

[dvgrn]

Is there a smaller form for this?

Code: Select all

x = 38, y = 22, rule = B3/S23
2o$2o7$21b2o$20b2o$15b2o5bo$14b2o$16bo6$22b3o$22bo12b2o$23bo11bobo$35b
o!

I can't seem to find anything smaller.
EDIT:
The block doesn't have to be in the same lane, however, the still life has to be a block.

Does "smaller" mean "fewer gliders", or "smaller bounding box"? And does "doesn't have to be in the same lane" mean that the output block can be anywhere relative to the input block, as long as there's a block there when the 180-degree reflection reaction is done?

Any other constraints on the lane of the return glider?

[bprentice]

Why is the forum dying? Currently there are only 8 people on line.

Brian Prentice

[C28]

Why is the forum dying? Currently there are only 8 people on line.

Brian Prentice

this is not an easy question. it seems like it is mostly because most people either don't know of conway's game of life or are just not interested.

Edit: it doesn't help that the forums doesn't have much for newcomers to the forums. there could at least be something like Scratch's "Welcome to Scratch", which is designed with newcomers in mind. just a thought.

[dvgrn]

Why is the forum dying? Currently there are only 8 people on line.

Brian Prentice

That might not be "dying", it might just be "an accurate count for a change". From Discord, 3 February 2022:

These connection issues should be gradually improving over the next couple of days, as I add rules to my server to swat out the ridiculously numerous bots that like wasting my server's resources. We're now down to 25 "guests" currently browsing the forums, which is far lower than the 70 or 80 that it's stayed reasonably consistently at for the last year or so.

[mniemiec]

Why is the forum dying? Currently there are only 8 people on line.

Another possible reason could be that since the creation of the Discord server, many people tend to hang out there, because it's less formal and feedback is much more immediate.

E.G. I keep one browser tab pinned to "my responses" here whenever I have a browser running, but that doesn't show up in the resident user count, and I only actually browse pages that have change recently a couple of times per day. I also keep Discord pinned in a browser tab (so I DO show up as online), but I also only check that server a couple of times per day, unless someone specifically mentions me.

[AlbertArmStain]

Is there a smaller form for this?

Code: Select all

x = 38, y = 22, rule = B3/S23
2o$2o7$21b2o$20b2o$15b2o5bo$14b2o$16bo6$22b3o$22bo12b2o$23bo11bobo$35b
o!

I can't seem to find anything smaller.
EDIT:
The block doesn't have to be in the same lane, however, the still life has to be a block.

Does "smaller" mean "fewer gliders", or "smaller bounding box"? And does "doesn't have to be in the same lane" mean that the output block can be anywhere relative to the input block, as long as there's a block there when the 180-degree reflection reaction is done?

Any other constraints on the lane of the return glider?

I didn’t clearly think about using a different lane.
When I said “smaller” I meant by population and not bounding box, next time I think I should specify that.

[dvgrn]

When I said “smaller” I meant by population and not bounding box, next time I think I should specify that.

Did your 4G invariant 180-degree turner come from this search by chris_c? That was a search for 90-degree turners, and it came up with several 3G->Gs, so a similar exhaustive search is likely to turn up a few 3G->(180-degree G) invariant turners.

- Does the block have to stay in the same place?
- Are there any constraints on the output lane?

[GUYTU6J]

Does anyone have discovery references for eater 5 and 7×9 eater?
Also,

How to design an incremental synthesis for 7×9 eater?
Partially related, is there any circumstance where 7×9 eater works but this synthesizable 8×8 variant doesn't?

[AlbertArmStain]

When I said “smaller” I meant by population and not bounding box, next time I think I should specify that.

Did your 4G invariant come from this search by chris_c? That was a search for 90-degree turners, and it came up with several 3G->Gs, so a similar exhaustive search is likely to turn up a few 3G->(180-degree G) invariant turners.

- Does the block have to stay in the same place?
- Are there any constraints on the output lane?

All I'm asking for is a 3G 180-degree turner.
I can't find the search anywhere, could you possibly link it?
EDIT:
Never mind, I found this:

My Serizawa method for handling the edge made me thinking: if we go for the design of "all at the same place with single 180 degree reflector", we don't need a real reflector, we can send a glider cluster (Gemini style), and get one glider back. Here is an example (3G->G single block 180 reflector):

Code: Select all

x = 32, y = 31, rule = B3/S23
7$8b2o$8b2o8$21b2o$15b3o2b2o$15bo6bo$16bo3$19bo$18b2o$18bobo!

[Herschel of Ostropol]

Is a 10 x 10 solid square of cells glider constructible? And if not is there a Garden of Eden predecessor?

[yujh]

Is a 10 x 10 solid square of cells glider constructible? And if not is there a Garden of Eden predecessor?

What, garden of edens aren’t meant to have predecessors. A pattern with predecessors doesn’t mean it must have glider synthesis, although I believe a 10x10 is not hard.