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Posted by u/dvgrn 2 years ago
AMA: I'm Dave Greene, an accidental expert on Conway's Game of Life
I drifted into the Conway's Life research community in 2001 when I won a small cash prize for a lucky discovery of something called a "boojum reflector". My involvement has gradually snowballed since then. Off and on I've helped maintain various Life-related mailing lists and blogs, the Life Lexicon, and more recently the conwaylife.com forums and LifeWiki.

Another thing I stumbled into was helping Nathaniel Johnson complete an improbably thorough 480-page Conway's Life textbook, with end-of-chapter exercises and everything. The book could be used to teach a college-level class on the subject. https://conwaylife.com/book/ has a free PDF download for the book.

So... I'm not the cleverest Lifenthusiast by a long shot, but for a random question about the Game of Life, I'm more likely to know something about it than at least 99.9999% of the world's population. Ask me anything!

HarHarVeryFunny · 2 years ago
We see people doing insane things nowadays with Conway's Life, such as simulating CPUs.

Two questions:

1) How are people building things this complex? Are there open source libraries and toolkits for this - building blocks for chunks of functionality that can be assembled?

2) For you, what are the most interesting, impressive and varied things that you've seen with Life? Is it just these increasing levels of complexity, or maybe something else?

dvgrn · 2 years ago
Question 1: There are really surprisingly few "standard libraries" or tools for this kind of thing. You would think we'd have a CA editor capable of doing object-based editing by this time -- like, copy in a complete device made out of reflectors and converters, each of which is made out of still lifes and oscillators, each of which is made out of cells, and you could do "group" and "ungroup" operations and snap to the right locations to fit the circuits together correctly.

But at the moment, pretty much all we have is tools to copy and paste rectangular sections of patterns at the cell level -- plus we've got good scripting tools (in Golly) that can be used to string together whatever pieces we might want, but it's up to individual pattern-builders to write those scripts for each specific purpose.

So our "library" is pretty much just the LifeWiki and a few other pattern repositories, and we borrow liberally from existing large constructions -- but when we're building something new, we usually just build flat bitmaps, not anything with built-in annotations or metadata.

Question 2: The thing that's been the most interesting to me in the last decade or so is the increase in collaboration. Projects used to be done by just one person more often than not -- but now a very large fraction of the biggest discoveries are completed via a large group effort over the course of a few weeks or month. One big recent example has been the RCT fixed-cost universal glider synthesis project, which needed contributions from quite a few people to solve all of the tricky little sub-problems:

  https://conwaylife.com/wiki/Reverse_caber-tosser

jaymzcampbell · 2 years ago
The Game of Life is a 2-dimensional cellular automata (CA), so given the 1-dimensional rule 110 has been proven to be universal / Turing-complete [1], it becomes less mysterious. Albeit the complexity of the system required to set it up to do anything "useful" would be prohibitive.

I'm currently finishing up my OU MSc and the project I picked was specifically around cellular automata - only in this case relating to them calculating any arbitary automatic sequence - which are sequences you can create from finite state machines - that really opened my eyes to the fact these sorts of very, very simple machines can, with the right (and rather complex) setup, be made to do pretty much whatever you want from a computational PoV. In that paper by Rowland and Yassawi they give a constructive proof to calculate the required update rules for a CA that outputs any particular automatic sequence. That itself gives some hints at some ways of deriving the input and rules for these systems to do some particular job. [2]

I know Wolfram often gets dunked on for ego/hubris but in Chapter 11 of a New Kind Of Science he goes into how the Rule 110 CA can be setup to "calculate" (output) other CAs. From there it starts to become a little less mysterious that these systems can generate behaviour you could imagine running on a CPU of some sort.[3]

[1] https://mirror.explodie.org/universality_in_elementary_cellu...

[2] https://arxiv.org/abs/1209.6008

[3] https://www.wolframscience.com/nks/chap-11--the-notion-of-co...

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bell-cot · 2 years ago
The basics, JIC anyone here is still unfamiliar with the Game:

https://en.wikipedia.org/wiki/Conway%27s_Game_of_Life

And generalizing Games from there:

https://en.wikipedia.org/wiki/Life-like_cellular_automaton

Question #1: How far has Lifeology(?) advanced since 2001, for people similar to your younger self (without awesome skills, or huge time investment) to have a chance at making their own lucky discoveries, and becoming modest Somebodies in the community?

Question #2: How highly (or otherwise) would you rate Wikipedia's articles on Conway's Game of Life, and closely-related topics?

dvgrn · 2 years ago
A really impressive number of discoveries have been made since 2001 -- there's been kind of a proliferation of new sub-fields, so it seems like there's never any shortage of things for newcomers to work on.

There are definitely areas that haven't really been explored fully yet, like the use of SAT solvers in new and inventive ways to tackle difficult Life problems that are currently just beyond our reach.

Just for example, there's the problem of finding a fast elbow for a 2c/3 "signal wire" --

  https://conwaylife.com/wiki/Wire#2c/3_wire
It's not clear if SAT solvers can be applied usefully to glider synthesis questions, like "is it possible to collide gliders to build a Sir Robin spaceship?" At the moment that particular question seems way beyond reach, but maybe in a few years we'll be running an AI that is experimentally setting up new SAT solver problems, and something will pop up that we just haven't managed to think of yet.

Question 2: Wikipedia's articles tend to be very good quality -- partly because if they weren't, there are a lot of Lifenthusiasts with some experience maintaining the LifeWiki who would immediately go and fix any technical errors that might show up on Wikipedia. But the really detailed documentation on Life is definitely kept in the LifeWiki, not on Wikipedia:

  https://conwaylife.com/wiki/

blastro · 2 years ago
Reminds me of the Busch-Gass Gambit in chess - something so new and mind boggling that it absolutely destroys the best chess engines in the world. Discovered through computer analysis. Insane to watch this opening played well.
kwhitefoot · 2 years ago
I was unfamiliar with JIC, had to read the sentence twice to make sense of it. :-)
mihaitodor · 2 years ago
Have you followed the https://codegolf.stackexchange.com/questions/11880/build-a-w... thread where Tetris was implemented using their Cogol (and low level QFTASM) programming language? I'm curious if that work led to any new insights and if it found any usage beyond implementing Tetris.
dvgrn · 2 years ago
Yup, the Quest for Tetris project caused an entertaining stir for a while. The people that worked on that were the best kind of "hacker" -- fearless experimenters who didn't let their lack of Life-specific knowledge get in the way of cobbling together an amazing structure that fit the bill for simulating Tetris.

The project has at least one unnecessary extra layer of abstraction in it, but somehow nobody has quite gotten around to rebuilding it 100x smaller. A "HashLife-friendly" version could run thousands of times more quickly in Golly.

Since then, several people have invented their own independent computer architectures in Conway's Life, so that kind of experimentation is still going on. See, e.g.,

  https://conwaylife.com/wiki/8-bit_programmable_computer

mihaitodor · 2 years ago
Thank you!
rosmax_1337 · 2 years ago
Why is Conway's Game of Life so interesting? Does it prove anything or lead to insightful discoveries? The game itself seems to me, like a fun little toy at best.
crdrost · 2 years ago
This won't directly answer the question, but just to give some added context: Note that in abstract mathematics (which is what Conway was doing here) you’re kinda creating building blocks, and you're kinda playing for “street cred” among the rest of the abstract mathematics community.

This is kind of true in all academic publishing, that your success is due to your publications’ ability to inspire follow-up publications. But for abstract mathematics the “street cred” follows three rules: you get more cred based on,

• the wimpier the building blocks look

• the larger and more complex the structures you can build with them

• the more memorable or intuitive the blocks are (so like marketing... SK-calculus is the same as lambda calculus but lambda can say “I am the abstract mathematics of template substitution!” while SK-calculus can't, directly.)

All a way to say that the field is full of “fun little toys” and the key about criterion (2) is that we have figured out how to build structures of arbitrary complexity in Life, because we have discovered it is Turing-complete. It therefore is also NP-hard and a lot of other good stuff. Really revitalized work into cellular automata by giving some good marketing, which led to Stephen Wolfram's success etc etc.

TimTheTinker · 2 years ago
Excellent info.

> which led to Stephen Wolfram's success etc etc.

Wolfram's A New Kind of Science takes the idea a bit too far, in my opinion. It's an exposition of the hypothesis that the underlying stratum of life and the universe is, like cellular automatons, discrete—and therefore can be understood in terms of discrete processes, which he views as analogous to real life. He points to emergence in cellular automatons as evidence that an analogous emergent phenomenon was the reason biological life came into existence.

Mathematically and philosophically, it's a very interesting idea, but I'd hope that at this stage in scientific history, we'd understand that step 2 to validating an interesting hypothesis is testing it.

TimTheTinker · 2 years ago
A simple set of rules leads to a fascinating array of emergent phenomena, which themselves can be utilized to do all sorts of interesting things.

In fact, the game of life is Turing complete -- you can build whole processors[0] or programming languages in it. You can even implement the game of life in the game of life. Someone did that and implemented infinite zooming between GOL levels.[1]

[0] https://github.com/nicolasloizeau/scalable-gol-computer

[1] https://oimo.io/works/life/

_akhe · 2 years ago
It shows that complex structures, importantly those with generative capabilities and other utilities, can evolve from a simple pattern.

It's a fun toy because it's implemented in pixels with arbitrary rules, but the concept is exportable to other domains.

The eeriness of it I think comes from that we still don't understand a lot about the world - concepts like consciousness, the origin of the universe, origin of life - or, any mystery where we don't understand how a whole became greater than the sum of its parts - when you see a model like this, it shows visually how such unknown complexities probably originated in far simpler forms.

When I see those epic Game of Life videos where there's a giant stealth bomber looking structure steaming across the screen creating sub-processes in its wake, to me it's like a blue whale moving through the ocean, or a vast alien spaceship silently yet steadily barreling through the void of space.

There's an ominous intelligence that seems to emerge out of what was once simple, binary, unconscious, incapable.

abetusk · 2 years ago
Conway's Game of Life (GoL) provides a clear demonstration that simple rules can lead to complex behavior. The complex behavior is deep in the sense that Conway's GoL is Turing Complete [0].

The local update rules provide an analogy to our universe with a kind of built in "speed of light" of how fast information can propagate in the system. Further, since there is a system clock of sorts, the system is massively parallel with further analogies to our universe.

The game looks like a toy but note that many profound models are also "toy-like". Ising systems, precolation models, Bethe lattices, self avoiding walks, etc. all provide seeding grounds for deep insights into our physical world. Just as an aside, I heard a quote, which I can't find anywhere, about how Maxwell playing with magnets could have been considered him playing with frivolous toys but his setup was critical to him figuring out the underlying mechanics of electromagnetism.

On one hand, I sort of agree that there's a lot of uninteresting exploration but on the other hand, taking a step back, GoL research is exploring the more general space of cellular automata and how it could potentially map to real world simulation. For example, how small can a system be before it can do arbitrary computation? Can all patterns emerge eventually (no, garden of eden style patterns)? What do rotationally invariant patterns looks like? Can you "copy" arbitrary patterns from some setup? If so, how fast? Is it dependent on how big it is, or how complex it is? etc. GoL provides a sandbox in order to answer these questions and potentially give insight into other systems as well.

In my opinion, one of the reasons for the popularity of GoL is because it was created right when computers became commodities, allowing hackers, amateur mathematicians and others to program something simple, that could be heavily optimized for limited hardware, and create intricate and complex behavior. There was a quote somewhere, that I'm also having trouble finding, about how, at one point, GoL simulations accounted for a significant portion of wasted compute.

[0] https://en.wikipedia.org/wiki/Conway%27s_Game_of_Life#Undeci...

aj7 · 2 years ago
Just leave physics out, and you’ll be OK.

God doesn’t play the GoL.

meschi · 2 years ago
It's a cellular automaton showing complex behavior emerging from very simple rules. Through especially crafted inputs you can simulate a Turing machine or Conway's Game of Life inside itself.
pavel_lishin · 2 years ago
> boojum reflector

That absolutely sounds like a codename from one of cstross's Laundry Files novels. (I think "boojum" was actually part of one, but I don't recall which.)

edit: found it, it was from A Colder War, which is a great novellette: https://www.infinityplus.co.uk/stories/colderwar.htm

sevenseventen · 2 years ago
The word "boojum" originates in Lewis Carroll's "The Hunting of the Snark," an amusing epic poem about the importance of negative testing.
lamename · 2 years ago
I'm interested. Scanning wikipedia, I'm missing the link with the importance of negative testing. Could you explain?
bombcar · 2 years ago
And also is given to a cactus-like tree: https://en.wikipedia.org/wiki/Boojum_tree
bradleyy · 2 years ago
I've been fascinated by Cellular Automata and the Game of Life ever since seeing the art installation of _Network IV_ by James Seawright. It was at Sea-Tac Airport, and has since been removed.

There's some debate whether it was the Game of Life or some other automata, but I remember the sounds of the relays clacking and the light bulbs humming so distinctly. It certainly had a "Game of Life vibe".

Are you aware of this art installation? Ever seen it?

dvgrn · 2 years ago
Hadn't heard of it. Looks like it was removed sometime in the 90's, maybe, so it's not too likely that there would be a good video of it in action.

https://www.reddit.com/r/Seattle/comments/1xzypl/something_i...

https://imgur.com/gallery/3zwVKc3

It does seem like the kind of thing I might have been drawn into staring at for hours and/or playing around with, kind of like the marble perpetual-motion machine I remember from a Toronto museum at around the same time period.

cauliflower99 · 2 years ago
Conway has said GOL is not something he is particularly pleased got as famous as it did. (Ref: https://youtu.be/R9Plq-D1gEk?t=600)

Why do you think that is?

Edit: This is the video I meant: https://www.youtube.com/watch?v=E8kUJL04ELA

gnramires · 2 years ago
What I got from his interviews is not that he disliked the GoL, it's just he disliked the GoL overshadowing everything else he did (basically, becoming the GoL guy). He personally didn't see much more interesting mathematics that could be done after answering basic questions like universality (although it's likely he wasn't aware of everything the community was up to). Also, it's clear he seemed to come to terms with it in his final interviews (including the second one you linked) :)

I've played around with several CAs and Conway's rules stands out to me as one of the most interesting still, for many reasons (like simplicity, interesting patterns, long lived structures).

travisjungroth · 2 years ago
Reminds me of Steve Paxton, an amazing dancer who passed away recently. He led a project called “Contact Improvisations”, which became a movement form called Contact Improvisation. He taught some classes and many others contributed. 50 years later, it’s still going strong. But, he didn’t embrace this role of “Contact Improv guy” that was really available to him. He just kept doing other stuff, even as this community exploded.

I think that’s partly the nature of pure researchers. They usually have something more interesting to them than what they got famous for, and they probably don’t want to lead an organization. This is different from BDFLs like Guido van Rossum and Rich Hickey. Neither type is good or bad, and I appreciate them all.

JoeDaDude · 2 years ago
A silly question and a PSA:

1. There was a two-player game called The Immigration Game [1] using GoL rules. Has anyone actually played this? Even better, has anyone developed an AI to play it? Is there really much of a game there?

2. The PSA: The Immigration Game was described in Lifeline, a 1970's era (typewritten!) newsletter about GoL. I managed to obtain a set of them. I've been planning to scan them and make them available online. I don't think there is any ground breaking info in them, after all, folk were programming on mainframes (surreptitiously).

[1]. https://boardgamegeek.com/boardgame/129088/the-immigration-g...

dvgrn · 2 years ago
My sense is that people don't usually play the Immigration Game for very long -- it just doesn't seem all that interesting to most folks ... and so there hasn't been much interest in developing a computer opponent for the game.

It seems to be rather difficult to convert cellular automata into any kind of playable game. If it's an arcade game then it's usually too arbitrary, and if it's a puzzle game then it's usually way too easy or way too difficult. There have been some good efforts, but they're mostly only playable by dedicated Lifenthusiasts, and that's ... well... not a very large market!

Re: the LIFELINE public service announcement -- no need to do the scanning and online-ing. That's been done already, though there's still some review and typing-up work left for someone to do:

  https://conwaylife.com/wiki/Category:Lifeline_issues