Thread for basic questions

[muzik]

Does anyone happen to still have any of the older versions of MJCell (before v.1.50)? The only ones I've been able to get are v.1.50 and v.1.51.

I've set up an archival index to keep track on what versions we have and what we don't.

I've also set up an index for Alan Hensel's old Java applet, if anyone happens to have older versions of that as well: https://bluemaxima.org/flashpoint/datah ... ife_applet

[mniemiec]

We can't officially call phoenix 1 just "the phoenix" (though the article does say that it gets referred to in exactly that way sometimes)... because its official name is "phoenix 1". It's referred to that way in a bunch of places, and anyway the number of phoenices is unlimited so it doesn't make much sense to call any particular one of them "the phoenix".

I always remember hearing it referred to as just "Phoenix", long before there was any notion of "official names". I have no idea who assigned it the name "Phoenix 1", but it's likely that somebody just randomly started calling it that, and the name caught on. Many names are like that.

I've found that I've assigned ad-hoc names to patterns, just because I needed to do so to identify them in my synthesis database, and those names later ended up becoming the "official names" just because nobody else had previously thought to name them.

It's a bit like the arbitrary nature of Unicode character names. All of Unicode reeks of "design by committee", with code blocks being expanded again into supplemental blocks and again as new characters get added ad-hoc as the need arises. There are many character names that don't make any sense, but they're that way just because "we named them that way initially, and our rules forbid us from changing them, even if the changes make more sense".

I seem to recall that the APL left-tack and right-tack characters particularly suffer from this. Unicode mandates the name, but not the glyph, so it can be a bit ambiguous which is meant, as the standard doesn't specify. Even worse, there are compound characters that are derived from these, some of which assume one direction, and some of which assume the other. There are also other characters whose names are obviously misspelled, but the standard forbids correcting the spelling retroactively.

[wwei47]

Is there any term for a tagalong like the one located where it is here?

Code: Select all

x = 60, y = 13, rule = B01e2c3i4e/S1e3y4et
8bo6b3o3b3o7bo$14bo6b4o5b3o5b3o$8b2o11b3o6b3o2bo19b4o$9bo11b4ob3ob2obo
b2o8b6o4b5o$7b2o5bo6b15o17b7o$16b3ob13ob2o18bo2bo$2o2bo2b4ob22o19b4obo
$16b3ob13ob2o18bo2bo$7b2o5bo6b15o17b7o$9bo11b4ob3ob2obob2o8b6o4b5o$8b
2o11b3o6b3o2bo19b4o$21b4o5b3o5b3o$8bo12b3o7bo!

[bubblegum]

Is there any term for a tagalong like the one located where it is here?

pushalong

[wwei47]

Is there any term for a tagalong like the one located where it is here?

pushalong

Doesn't a pushalong go in front of the entire spaceship? This one is between two parts of the spaceship, and next to a third part.

[bubblegum]

Doesn't a pushalong go in front of the entire spaceship? This one is between two parts of the spaceship, and next to a third part.

It is in front of the spaceship.

[wwei47]

It is in front of the spaceship.

Then I should have made myself more clear. See the extra four cells in the bottom spaceship? That's the tagalong that I'm asking about.

Code: Select all

x = 60, y = 43, rule = B01e2c3i4e/S1e3y4et
8bo12b3o7bo$21b4o5b3o5b3o$8b2o11b3o6b3o2bo19b4o$9bo11b4ob3ob2obob2o8b
6o4b5o$7b2o5bo6b15o17b7o$16b3ob13ob2o18bo2bo$2o2bo2b4ob22o19b4obo$16b
3ob13ob2o18bo2bo$7b2o5bo6b15o17b7o$9bo11b4ob3ob2obob2o8b6o4b5o$8b2o11b
3o6b3o2bo19b4o$21b4o5b3o5b3o$8bo12b3o7bo18$8bo6b3o3b3o7bo$14bo6b4o5b3o
5b3o$8b2o11b3o6b3o2bo19b4o$9bo11b4ob3ob2obob2o8b6o4b5o$7b2o5bo6b15o17b
7o$16b3ob13ob2o18bo2bo$2o2bo2b4ob22o19b4obo$16b3ob13ob2o18bo2bo$7b2o5b
o6b15o17b7o$9bo11b4ob3ob2obob2o8b6o4b5o$8b2o11b3o6b3o2bo19b4o$21b4o5b
3o5b3o$8bo12b3o7bo!

[ihatecorderships]

Why is quadpole and even quadpole on ship way more common than tripole? Is it because of some common predecessors?
Edit: I think quadpole on ship should be called quadpole tie ship, right?

[dvgrn]

Why is quadpole and even quadpole on ship way more common than tripole? Is it because of some common predecessors?
Edit: I think quadpole on ship should be called quadpole tie ship, right?

This question actually came up quite recently on another thread, and got a reasonable answer:

How is quadpole on ship more common than tripole?

Fleet+century reaction:

Code: Select all

x = 11, y = 13, rule = B3/S23
8bo$9bo$9bo$6b3o2$4b2o$3bobo$3b2o$b2o$obo$2o!

(Strictly speaking those are a ship-tie and a century cousin but whatever)

[cgoler2]

Why is it that the very long fuse in "very long trans-fuse with two tails" has the same length as the fuse in "cis-fuse with two tails"?

[mniemiec]

Why is it that the very long fuse in "very long trans-fuse with two tails" has the same length as the fuse in "cis-fuse with two tails"?

This is because the nomenclature in both cases starts with the shortest possible fuse, with prefixes indicating additional length, but what is shortest for the cis case is much longer than for the trans case, because in the cis case, the parts at the ends can interfere with each other. It is similar for "hook with tail" and "cis hook with tail".

[wwei47]

Would this P4 be considered a honey farm hassler?

Code: Select all

x = 32, y = 15, rule = B3/S23
6b3o$7bo2$6b3o17b3o$5bo3bo15bo3bo$4bo5bo13bo5bo$o2bo7bo2bo8bo7bo$2obo
7bob2o8bo7bo$o2bo7bo2bo8bo7bo$4bo5bo13bo5bo$5bo3bo15bo3bo$6b3o17b3o2$
7bo$6b3o!

[dvgrn]

Would this P4 be considered a honey farm hassler?

I'm not any kind of expert on this, but I wouldn't think so. Without the tub in the middle, the octagon isn't a standard HF predecessor. And hasslers are usually sparkers that are stable even when the thing-being-hassled isn't within reach. And they usually either move or rephase the object being hassled, they don't just support it.

You'd have to invent some new terminology, like "four pre-TLs co-hassling a pre-HF", where "co-hassling" means "simultaneously hassling and being hassled"... but let's not go there!

[GUYTU6J]

A classical ship + dot → LoM reaction is triggered by using a three-glider spark-insertion, as shown below in red. Can the dot be delivered from right?

Code: Select all

x = 6, y = 17, rule = LifeHistory
3.2A$2.A.A$2.2A2$4.A2$2.D$2.2D$.D.D3$3.3D$3.D$4.D$3D$2.D$.D!
#C [[ THUMBNAIL THUMBSIZE 4 ]]

The clearance below that dot has to be very high. For example, the G + fishhook reaction doesn't work for me.

Code: Select all

x = 8, y = 7, rule = LifeHistory
5.A.A$5.2A$6.A$2.2A$D2.A$3A$A!

[Entity Valkyrie 2]

Would this P4 be considered a honey farm hassler?

Code: Select all

x = 32, y = 15, rule = B3/S23
6b3o$7bo2$6b3o17b3o$5bo3bo15bo3bo$4bo5bo13bo5bo$o2bo7bo2bo8bo7bo$2obo
7bob2o8bo7bo$o2bo7bo2bo8bo7bo$4bo5bo13bo5bo$5bo3bo15bo3bo$6b3o17b3o2$
7bo$6b3o!

The central object evolves into a HF in a different way than the standard, so the name can be confusing.

Code: Select all

x = 26, y = 9, rule = B3/S23
3b3o$2bo3bo14b3o$bo5bo12bo3bo$o7bo10bo5bo$o7bo10bo5bo$o7bo10bo5bo$bo5b
o12bo3bo$2bo3bo14b3o$3b3o!

[mniemiec]

Would this P4 be considered a honey farm hassler? ...

Even though one phase of it superficially resembles the exterior of one phase of the honeyfarm evolution, this is purely coincidental, because:
1) It doesn't get that way in any way that resembles how a honeyfarm does.
2) What it does afterwards is very different than what a honeyfarm does; i.e. no steps in the honeyfarm evolution sequence actually occur.
3) In the honeyfarm, this phase occurs as the pattern is expanding; here, it happens as it is imploding.
4) The absence of a tub is not just coincidental, it's vital; putting the tub inside would destroy the oscillator - so this phase is not and MUST NOT BE the same as the corresponding phase in the honeyfarm evolution.

[hotdogPi]

When is the earliest this p120 oscillator could have been discovered? (It was actually discovered this year.)

Code: Select all

x = 86, y = 86, rule = B3/S23
37b2o$37b2o5$38bo$36b2ob2o2$35bo5bo2$35b2obob2o3$48bobo$48bo3bo$52bo5b
2o$48bo4bo4b2o$52bo$48bo3bo$48bobo6$16b2o$16b2o2$42bo$41bobo$40bo3bo$
17bo22bo3bo$15b2ob2o20b2ob2o2$14bo5bo53bobo$74bo3bo$14b2obob2o57bo5b2o
$74bo4bo4b2o$78bo$52b3o19bo3bo$31b3o18bo2bo18bobo$30bo2bo22bo$29bo22bo
2bo$9bobo18bo2bo18b3o$7bo3bo19b3o$7bo$2o4bo4bo$2o5bo57b2obob2o$7bo3bo$
9bobo53bo5bo2$41b2ob2o20b2ob2o$41bo3bo22bo$41bo3bo$42bobo$43bo2$68b2o$
68b2o6$35bobo$33bo3bo$33bo$26b2o4bo4bo$26b2o5bo$33bo3bo$35bobo3$44b2ob
ob2o2$44bo5bo2$45b2ob2o$47bo5$47b2o$47b2o!

[dvgrn]

When is the earliest this p120 oscillator could have been discovered? (It was actually discovered this year.)

Hard to say. Not absolutely impossible in the early 1970s, but so unlikely that if we re-ran the history of Life to 1975 a billion times, it probably wouldn't have been discovered even once. A lot of early simulators were limited to sizes around 80x80 for speed and memory reasons.

Certainly it was within reach by the mid-1980s (HashLife was invented in 1984, and somebody might have taken an interest in doing randomized experiments along the lines of Nivasch's 'Random Agar', twenty years earlier.) But it still wasn't likely then, because this wouldn't show up in a Random Agar search -- at least, I don't think there's a way for multiple copies to support each other -- so it would have required a lot of search time at a time when CPU-hours were expensive, using a program that nobody had thought of writing.

[ihatecorderships]

Are diagonal photons possible in an INT rule? B0 is allowed.

[MathAndCode]

Are diagonal photons possible in an INT rule? B0 is allowed.

No, but they are possible in three-state rules.

[ihatecorderships]

Are diagonal photons possible in an INT rule? B0 is allowed.

No, but they are possible in three-state rules.

Why though?

[MathAndCode]

Why though?

In two-state rules, any pattern that expands by c diagonal at one of its corners must also do so at its other corners. In three-state rules, the other corners can be buffer/sheath cells.

[pcallahan]

I finally got a chance to study and think about Gemini after all these years and I had a question that maybe other people have considered or even answered by implementing it.

Question
The main trick to Gemini (and the reason for its name) is having symmetrical constructors on each end of the glider lanes containing instructions. What I wondered is whether you could replace one end with something a lot "dumber" than a constructor. I.e., at one end, you have all the constructor logic, and at the other, you have nothing but a spartan reflector sufficient to echo back the instruction stream. It would be the job of the universal constructor to move this end along as well as copying itself at its own end as it does now.

I think the tools exist to implement this: for most of the life of the far-end reflector, it would only receive and echo a single stream of gliders. As the constructor was ready to move, it would send a salvo sufficient to erase the reflector and use a slow construction to build a new one just in time to receive and echo the shifted instruction stream.

Alternatively, the far end could be determined as simply as the placement of a block. This would require the universal constructor to send a series of block push/pull salvos rather than single gliders. Because you need one salvo per bit of instruction, this is less efficient overall, though it optimizes the far end for simplicity.

Note: I realize that the symmetrical arrangement makes it a lot simpler to guarantee that both ends of the spaceship move in sync, and since the constructors are compact compared to the instruction stream, there's not a lot of benefit in terms of the usual measures of pattern size or complexity. I'm not sure what it "optimizes" except some form of the DRY principle. I am just curious if this is feasible (or I have missed an objection) and if anyone has built something like this.

OK, another question
Independent of whether we have a constructor at both ends or not, has anyone built a Gemini-like spaceship that uses streams of LWSSs instead of gliders to store the instructions? This would be less compact overall, but it would minimize one of the dimensions. It seems straightforward given all the ways to convert between gliders and LWSSs though I imagine it would add to the complexity.

[Macbi]

OK, another question
Independent of whether we have a constructor at both ends or not, has anyone built a Gemini-like spaceship that uses streams of LWSSs instead of gliders to store the instructions? This would be less compact overall, but it would minimize one of the dimensions. It seems straightforward given all the ways to convert between gliders and LWSSs though I imagine it would add to the complexity.

https://conwaylife.com/wiki/Orthogonoid

[dvgrn]

Question
The main trick to Gemini (and the reason for its name) is having symmetrical constructors on each end of the glider lanes containing instructions. What I wondered is whether you could replace one end with something a lot "dumber" than a constructor. I.e., at one end, you have all the constructor logic, and at the other, you have nothing but a spartan reflector sufficient to echo back the instruction stream. It would be the job of the universal constructor to move this end along as well as copying itself at its own end as it does now.

It's a known method. The linear propagator is the only completed self-constructor to pull off this trick. It isn't a spaceship, though, and it's full of what would now be considered to be incredibly archaic technology -- it was built in 2013, before an automatic compiler (slsparse) was available, and also before single-channel construction technology existed.

Nowadays it would be quite easy to compile a version of the linear propagator that self-destructed after copying to any (X, Y) offset you might want (and thus became a usually-oblique spaceship). It would probably also be built as a diamond shape -- or maybe an octagon if we wanted to show off a bit -- instead of a long straight boring diagonal line that causes mild heartburn for Golly HashLife. Somebody should do that. If a thread gets started I'll happily provide help. The closest thing we currently have to this kind of technology is the loopship, I think, but that takes glide-symmetry shortcuts again so it's not quite the same.

Note: I realize that the symmetrical arrangement makes it a lot simpler to guarantee that both ends of the spaceship move in sync, and since the constructors are compact compared to the instruction stream, there's not a lot of benefit in terms of the usual measures of pattern size or complexity. I'm not sure what it "optimizes" except some form of the DRY principle. I am just curious if this is feasible (or I have missed an objection) and if anyone has built something like this.

The disadvantage of the symmetrical arrangement is that it limits you to boring diagonal or orthogonal directions of travel, unless you double the amount of circuitry or use weird complicated tricks that kind of go against the Keep It Simple spirit.