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Flag September 13, 2012 2:46 AM PDT
A year or two ago, I created a combo that proves Magic to be Turing complete. I put up a little website about it. Now it's doing the rounds of the internet (Reddit, BoingBoing, Kotaku, Metafilter, Slashdot, Mark Rosewater's Tumblr), so I thought I really ought to post it on the official Wizards boards.

The basic idea is to assemble a universal Turing machine out of Magic cards, so that a massive cascading sequence of triggered abilities occurs which simulates computation of a Turing machine, without needing any interaction from the players at all. It's mainly a load of ETB and LTB triggers, with the core being six copies of (coexisting via ), all extensively hacked with and .

Q: How do you make a tape extending arbitrarily far in two directions with a "step left" and "step right" operation?
A: The tape to the left of the head is a series of Ally tokens, one 1 toughness away from dying, one 2 toughness away, etc; and the tape to the right is a similar series of Zombie tokens. To move left, we and (creature types ). This causes the smallest Ally to die, and a different ability triggers depending on what colour it was.

Q: How do you simulate the vital Turing machine concept of multiple states?
A: Phasing! All the Teysas are enchanted with or similar, and we arrange for the machine to cast whenever it needs to change state.

Q: How the heck do you cast an instant as a triggered ability?
A: , with help from , , , , , and lots of . Simple, right?

Q: Can you really prevent players needing to do anything?
A: ...Almost. The key operation "Give all Allies +1/+1" is accomplished via , which unfortunately has a "you may" in his rules text. So the cascade of triggered abilities isn't completely requiring no input from the players: one player has to effectively keep saying "yes" every time Kazuul Warlord or asks him "do you want to do this?" Another player has to similarly keep saying yes every time asks him the same question. But other than those "always say yes" operations, there's no interaction by the players required at all.

Q: Does this mean we can implement Magic Online inside another game of Magic?
A: Theoretically, yes.  But it might take quite a long time to get past the loading screen.

Full details at www.toothycat.net/~hologram/Turing/
Flag September 13, 2012 3:18 AM PDT

I actually thought about this a week ago. I was thinking "Magic cards interact with each other, perhaps you could build a computer out of a combination of them."

But I almost instantly abandoned the idea because I remembered that Magic was able to emulate sentience with .

Flag September 13, 2012 6:11 AM PDT
ALEXTFISH:

So what do you plan to use it for?

will parts of it be able to work better than a classical turing machine?

Or is it just something you wanted to figure out and did?
Flag September 13, 2012 7:30 AM PDT

Sep 13, 2012 -- 6:11AM, wickeddarkman wrote:

ALEXTFISH:

So what do you plan to use it for?

will parts of it be able to work better than a classical turing machine?

Or is it just something you wanted to figure out and did?

Ha! No, I don't think it's useful for anything much. Turing machines are only really useful as theoretical ideas anyway. It's incredibly cool for people who know about what Turing machines and Magic are.

In particular, I think it's the first demonstration of Turing completeness in the rules of any tabletop game. I don't think there are any other board games or card games whose rules accommodate the complexity required to make a Turing machine (and I've played a few hundred).

I created it basically because someone asked me "Is Magic Turing complete?" I figured the answer must be yes, and started to try to prove it, and eventually (with help from a few friends) came up with that intricate combo.

I suppose one possible way to use it is that there are certain questions about Magic that it proves, or proves to be unanswerable. For example, the question "is this an infinite loop?" is impossible to tell if the loop in question is calculating, say, whether every even integer greater than 2 can be expressed as the sum of two primes (or any similar unanswered problem). So we've proved there are some game states in Magic where it's impossible to tell whether the game is a draw or not.

Flag September 13, 2012 8:06 AM PDT
You are my favourite Magic player for doing this.
Flag September 13, 2012 8:19 AM PDT

Sep 13, 2012 -- 7:30AM, alextfish wrote:

So we've proved there are some game states in Magic where it's impossible to tell whether the game is a draw or not.

oh, you.

Flag September 13, 2012 8:26 AM PDT
also if you let yourself use un cards, on lets you play the role of warlord without involving a "may". doesn't eliminate the player choices but reduces them.

or, in real magic world, put out a second noxious ghoul of each type and a . then you have each creature getting +1/+1 and each non-X creature getting -2/-2, resulting in each non-X creature getting -1/-1. with no choices made.

Flag September 13, 2012 8:32 AM PDT
also you can reduce them by finding a way to sacrifice/kill the chancellor and having in play. (with a way to remove the counter, obviously, but that's trivial.) I don't know a way to remove the chancellor decision though, that one's tricky.

Flag September 13, 2012 9:33 AM PDT
Good stuff. The concept of the stack where each action resolves in sequence is the same as the stack an operating system's kernel works with, right?
Flag September 13, 2012 10:02 AM PDT

Sep 13, 2012 -- 8:26AM, razorborne wrote:

or, in real magic world, put out a second noxious ghoul of each type and a . then you have each creature getting +1/+1 and each non-X creature getting -2/-2, resulting in each non-X creature getting -1/-1. with no choices made.

I haven't looked at all this stuff, but isn't the potential to stack the triggers relevant in this scenario?

Flag September 13, 2012 10:07 AM PDT

Sep 13, 2012 -- 10:02AM, Mown wrote:

Sep 13, 2012 -- 8:26AM, razorborne wrote:

or, in real magic world, put out a second noxious ghoul of each type and a . then you have each creature getting +1/+1 and each non-X creature getting -2/-2, resulting in each non-X creature getting -1/-1. with no choices made.

I haven't looked at all this stuff, but isn't the potential to stack the triggers relevant in this scenario?

he uses multiple players to force the triggers to work in the necessary order, so no decisions need be made there. the only decision that needs to be made if you follow my suggestion is which order to stack the identical ghoul triggers, and, if that's too much decision, you can just add in a fifth player whose only purpose is to control two of the ghouls.

Flag September 13, 2012 10:10 AM PDT

Sep 13, 2012 -- 10:02AM, Mown wrote:

Sep 13, 2012 -- 8:26AM, razorborne wrote:

or, in real magic world, put out a second noxious ghoul of each type and a . then you have each creature getting +1/+1 and each non-X creature getting -2/-2, resulting in each non-X creature getting -1/-1. with no choices made.

I haven't looked at all this stuff, but isn't the potential to stack the triggers relevant in this scenario?

At first I thought so - I thought this would lead to a player being forced to choose the order of multiple triggers to go on the stack, which is something I'm avoiding (it's the whole reason the game is a 4-player game not just a duel).

But I think this could actually work. When an Ally ETBs under A's control:

B's for non-Allies triggers
C's triggers
D's for non-Allies triggers
A's triggers
A's Goldnight Commander resolves, pumping everything
D's Ghoul resolves, neutralising the pump to the non-Allies
C's Aether Flash happens, shrinking the new Ally to the right size
B's Ghoul resolves, giving a net shrink to the non-Allies

Wow. Yes, that looks like it'd actually work. Fantastic suggestion, razorborne: I'll work through the details and see if it all works out, but I'm cautiously optimistic right now. Yay for Avacyn Restored bringing better cards for the Turing machine

We'd still need a way to avoid the "may" in 's text though. So far my best ideas are or , both of which would need me to move away from Noxious Ghouls and Goldnight Commanders to more permanent solutions, and then we're back to with his "may" again.

Flag September 13, 2012 10:34 AM PDT

Sep 13, 2012 -- 10:10AM, alextfish wrote:

We'd still need a way to avoid the "may" in 's text though. So far my best ideas are or , both of which would need me to move away from Noxious Ghouls and Goldnight Commanders to more permanent solutions, and then we're back to with his "may" again.

this is, of course, the real problem. (also worth noting that at the very least players will have to actively pass priority every time, so player input is never actually fully removed.) the only ways I can find to cast instants without choices are , which has exactly the same problem of needing to be played itself, and and which, as you mention, require you to move away from temporary +1/+1 and -1/-1 options to counter-based methods. can play commander in that case, but you still need a -1/-1 option. hmm. the best I can find is and something that blinks whenever you play a creature (I don't know that that device exists) but then neither piece is discriminating about creatures of a specific type, meaning neither piece can act as the reader of which type you want to buff. I think you're stuck with the chancellor for now.

Flag September 13, 2012 10:47 AM PDT
I opened your website and immediately thought, "There's no way I'm getting through all of this."
I opened the Wikipedia page for Turing Machine and immediately thought, "There's no way I'm going to understand this."

But something kept me going, and I now have a basic understanding of Turing Machines and I actually read your entire site! Thanks for introducing me to this whole concept, and amazing work figuring out how to do this in Magic. It's unfortunate that we now know it isn't actually universal (according to Wikipedia anyway), but the groundwork is still awesome, and it sounds like you've already made a truly universal one with your 18-color version.

Also, kudos to razoborne for making a contribution so quickly.

tl;dr I'm in love with automated logical processes and this is awesome.

Edit: Reading the Wikipedia article further, I see that the validity of Alex Smith's proof is in debate. Just wanted to ammend my above statement about the (2, 3) Turing machine not being universal.
Flag September 13, 2012 11:44 AM PDT

Maybe you're just trying to force it because you feel that there is some academic reward, but there isn't. People who have completed far greater works have yet failed to receive the grandeur you might be expecting to get for completing this. For example, take a look at John von Neumann, he's contributed so much and seemingly for nothing. The world barely recognizes him today, he isn't even a vaguely well known figure. Now take a look at Steve Wozniak, he was all the muscle behind Apple. He is the one who did all the hardest work (like the electrical engineering) and even most Apple users don't even know he exists. They (and everyone else) give all the credit to his right hand man, Steve Jobs. Not saying that Jobs doesn't deserve credit, and there are hidden elements to this (like Wozniak's hidden nature, preferring to stay under the radar), but it's another example of how people who contribute extreme measures get nothing out of it.
Flag September 13, 2012 11:56 AM PDT

Sep 13, 2012 -- 10:07AM, razorborne wrote:

he uses multiple players to force the triggers to work in the necessary order, so no decisions need be made there. the only decision that needs to be made if you follow my suggestion is which order to stack the identical ghoul triggers, and, if that's too much decision, you can just add in a fifth player whose only purpose is to control two of the ghouls.

Right. I'll see if I can bother understanding all this before I say anything more.

Also, as an advice, ignore the post above me unless you want him to derail your entire thread. Although it's not unlikely that you have bumped into him before, I haven't seen you around these parts.

Flag September 13, 2012 12:26 PM PDT
Fascinating.
Flag September 13, 2012 2:39 PM PDT

Sep 13, 2012 -- 11:44AM, GM_Champion wrote:

, , . it's completely possible to set this up within the constraints of a real game.

Flag September 13, 2012 3:18 PM PDT

Sep 13, 2012 -- 11:44AM, GM_Champion wrote:

Maybe you're just trying to force it because you feel that there is some academic reward, but there isn't. People who have completed far greater works have yet failed to receive the grandeur you might be expecting to get for completing this. For example, take a look at John von Neumann, he's contributed so much and seemingly for nothing. The world barely recognizes him today, he isn't even a vaguely well known figure. Now take a look at Steve Wozniak, he was all the muscle behind Apple. He is the one who did all the hardest work (like the electrical engineering) and even most Apple users don't even know he exists. They (and everyone else) give all the credit to his right hand man, Steve Jobs. Not saying that Jobs doesn't deserve credit, and there are hidden elements to this (like Wozniak's hidden nature, preferring to stay under the radar), but it's another example of how people who contribute extreme measures get nothing out of it.

I think you are both missing the point and ascribing motivations that are not present.

Flag September 13, 2012 4:35 PM PDT

Sep 13, 2012 -- 11:44AM, GM_Champion wrote:

He didn't go outside the bounds.  As far as recasting instants and sorceries, there's any number of ways he could do that (, , , etc).  The only one that comes close is the 6 non-token Teysas, but it's a 4 player game.  It's perfectly within the rules for there to be 6 copies of a card among 4 people.

Also, why did you link to Unifying Theory?

Flag September 13, 2012 5:28 PM PDT

Sep 13, 2012 -- 7:30AM, alextfish wrote:

I suppose one possible way to use it is that there are certain questions about Magic that it proves, or proves to be unanswerable. For example, the question "is this an infinite loop?" is impossible to tell if the loop in question is calculating, say, whether every even integer greater than 2 can be expressed as the sum of two primes (or any similar unanswered problem). So we've proved there are some game states in Magic where it's impossible to tell whether the game is a draw or not.

The problem is that this is only true if you can find the version without any optional parts, unfortunately.

Flag September 13, 2012 10:04 PM PDT
Prepared for encoming Phyrexian armageddon.
Flag September 13, 2012 10:29 PM PDT
I never looked into the concept. My comment is based on the details of exceeding the card limit of four (in the event of such a thing). I didn't have the time to check into it and I just wanted to drop my insight on the matter in case more than 4 actual copies were being used. Sorry for the misunderstanding.
Flag September 13, 2012 11:15 PM PDT
You crashed the Matrix.

Could someone create this situation in MTGO and compute something simple? This becomes ten times more epic if it happens. I'd settle for a video of it happening at a table, to show off the idea.

Sep 13, 2012 -- 7:30AM, alextfish wrote:

So we've proved there are some game states in Magic where it's impossible to tell whether the game is a draw or not.

With Un-sets, this has been possible for a long time. All you need to do is create a physically impossible task that must be completed. Make a token of using steel dice to delay the game until someone aquires some heavy machinary. Pay half a mana into , then force shuffling of librarys. Doing this in normal magic is amazing. Please post in Q and A for a check and a ruling on what happens when the game state is that way.

It just occurred to me, you could use this to create a game state that will take longer to resolve than the lifetime of the universe. If you do this with a clearly resolvable game state (multiplying two very large numbers) you could...hmmm...set a universal record? Make a judge's head explode?

It's too bad MaGo isn't writing anymore, he'd have fun with this.

Flag September 14, 2012 5:05 AM PDT
I'm not sure you could do it on MTGO. is on there? how about ? then again carnival isn't necessary if you give A a , the aether flash, and give it a . or if for some reason you can't animate all enchantments you can just use and then it.

Flag September 14, 2012 5:24 AM PDT
RazorBorne, all those cards are on MTGO. Only some of Ice Age block and earlier is missing.
Flag September 14, 2012 7:24 AM PDT

Sep 14, 2012 -- 5:24AM, EyeHunter wrote:

RazorBorne, all those cards are on MTGO. Only some of Ice Age block and earlier is missing.

oh okay wasn't sure. I don't play MTGO.

Flag September 14, 2012 12:06 PM PDT
I want to voice my praise and admiration for an amazing feat.

Since the Turing tape is built of tokens, it didn't seem immediately obvious to me that the four-of rule would interfere. However, since a particular type of token is required, and cards are needed to generate tokens, I suppose that is where the problem comes in, as opposed to in the construction of the "machine", the tape reader and player, itself.

Since the players are required to say "yes" to some actions, though, this may not meet some definitions of "Turing-completeness" as applied to a game... but the fact that it can be used to compute anything with the cooperation of the players does mean that it meets a reasonable definition of Turing-completeness.
Flag September 14, 2012 1:57 PM PDT

Sep 14, 2012 -- 5:24AM, EyeHunter wrote:

RazorBorne, all those cards are on MTGO. Only some of Ice Age block and earlier is missing.

Does MTGO handle 4 way multiplayer?

Flag September 14, 2012 2:08 PM PDT
can easily be engineered to create tokens of any type, color, and size, and it can be reset at will with +. Even if a single player is going to be responsible for bringing almost all the cards involved, they can, since all sorts of Clone effects would suffice for the fifth and sixth copies of Teysa, and likewise for extra Cloaks of Invisibility.
Flag September 14, 2012 4:19 PM PDT

Sep 14, 2012 -- 1:57PM, Dr_Demento wrote:

Sep 14, 2012 -- 5:24AM, EyeHunter wrote:

RazorBorne, all those cards are on MTGO. Only some of Ice Age block and earlier is missing.

Does MTGO handle 4 way multiplayer?

Up to six, but it gets ugly fast.

Flag September 14, 2012 8:19 PM PDT
So, is using MTGO to simulate a computer and thus steal their server time for calculations a violation of the terms of use policies?

I mean, you could just buy a computer with orders of magnitude larger processing power for the cost of a subscription, but details.
Flag September 14, 2012 8:49 PM PDT
Last I checked, Magic Online has a limit of 200 tokens at a time, so if the tape needs to be longer than that to express your calculation, you're out of luck anyway.
Flag September 15, 2012 4:49 AM PDT
Heh. In my two attempts to run the combo on MTGO, I've indeed used the - trick to animate followed by a kicked . Infinite mana is definitely useful: since I'm already using and making my other creatures Allies, I use the - combo for that. Most useful in bootstrapping it all is making all 4 decks contain 4x , which will happily block each other at every opportunity: that makes the combo much quicker to set up. It's also very valuable to have a with  to pass things around between the players. But MTGO doesn't let you make multiplayer games with no time limit; 2h or 2h30 is the longest it lets you give each player, and even my machine chugs when running 4 copies of the MTGO client, such that even using F4 and F6 as much as possible, the driving player runs out of time. (It doesn't help that 's effects only display if the creature type is singlular in the original rules text! So hacking , you have to remember which ones you've evolved...)

It's looking like in order to make a proper universal Turing machine, I can't use the 2-state-3-colour one; that one needs the tape to be initialised in an infinitely nonrepeating way to do computation. It seems that 2-state-18-colour is what we need. That can be accomplished with creature types instead of colours, using loads and loads of s. Even that is doable on MTGO: there are enough variations to get 36 nontoken Reanimators easily, and if each deck has 4 of each of , and , that's enough for 36 phasing enchantments. Version 5 of the Turing machine will have all the details when I get it online.
Flag September 15, 2012 6:46 AM PDT
what are you gonna use for the +1/+1 and -1/-1? you can get a non-may +1/+1 through hacking s and but I don't see a way to give non-may -1/-1s based on color. or may-based ones, for that matter.

PS: is there a way to force you to make copies of something as a triggered ability? if so you can use two s as long as bird isn't one of your key creature types.
Flag September 15, 2012 10:57 AM PDT

Sep 15, 2012 -- 6:46AM, razorborne wrote:

what are you gonna use for the +1/+1 and -1/-1? you can get a non-may +1/+1 through hacking s and but I don't see a way to give non-may -1/-1s based on color. or may-based ones, for that matter.

PS: is there a way to force you to make copies of something as a triggered ability? if so you can use two s as long as bird isn't one of your key creature types.

I don't know if it's possible to eliminate all "may"s yet. As version 5 currently stands, it's still using with his "may". (Loads of let me make a complex chain of inference where anything of creature type A, B or C is therefore also of type D, and any D or E is also an F, etc.)

I have a couple of ideas. It's possible I could cause to repeatedly enter and leave the battlefield, perhaps by making and killing s. Or I may be able to move to a different model where each step of the machine is on a different turn, so I can use things like or (cast via or and recycled with an empty library and a ; other players having empty libraries and s or similar) to damage a relevant subset of the tokens on the tape. makes the damage into -1/-1 counters.

(Ah, darn, is another "may", so not him then. But something similar.)

I'm not sure I see how would particularly help. I might be able to do something with there, although might interfere.

Flag September 16, 2012 8:51 AM PDT

Sep 15, 2012 -- 10:57AM, alextfish wrote:

Sep 15, 2012 -- 6:46AM, razorborne wrote:

what are you gonna use for the +1/+1 and -1/-1? you can get a non-may +1/+1 through hacking s and but I don't see a way to give non-may -1/-1s based on color. or may-based ones, for that matter.

PS: is there a way to force you to make copies of something as a triggered ability? if so you can use two s as long as bird isn't one of your key creature types.

I don't know if it's possible to eliminate all "may"s yet. As version 5 currently stands, it's still using with his "may". (Loads of let me make a complex chain of inference where anything of creature type A, B or C is therefore also of type D, and any D or E is also an F, etc.)

I have a couple of ideas. It's possible I could cause to repeatedly enter and leave the battlefield, perhaps by making and killing s. Or I may be able to move to a different model where each step of the machine is on a different turn, so I can use things like or (cast via or and recycled with an empty library and a ; other players having empty libraries and s or similar) to damage a relevant subset of the tokens on the tape.

(Ah, darn, is another "may", so not him then. But something similar.)

I'm not sure I see how would particularly help. I might be able to do something with there, although might interfere.

never mind on the buzzard, I think I misinterpreted what you were going for. looking forward to version 5.

Flag September 17, 2012 5:53 AM PDT
VorpalAuroch over on Reddit suggests making enter/leave the battlefield, which I think may be the best option I've heard so far.
Flag September 17, 2012 7:38 AM PDT
Unfortunately, that isn't going to be extensible to anything beyond Shamans, since reentering a zone causes object modification to reset, and it's not even possible to keep re-hacking with Artificial Evolution because the ability has already triggered by the time it could be used, and it can't touch triggered abilities that are already on the stack.

Even making token copies of a Rage Forger doesn't work because layer-3 effects aren't copiable.
Flag September 17, 2012 12:41 PM PDT
If you cast on a spell, the effect will continue to apply to the permanent it becomes (see rule 400.7a). If you change's Shaman to some other creature type, it'll both be that new type and give counters to other creatures you control that have the new type.
Flag September 17, 2012 1:33 PM PDT
This is the best thread in a few years.
Flag September 17, 2012 2:14 PM PDT

Sep 17, 2012 -- 12:41PM, adeyke wrote:

If you cast on a spell, the effect will continue to apply to the permanent it becomes (see rule 400.7a). If you change's Shaman to some other creature type, it'll both be that new type and give counters to other creatures you control that have the new type.

that requires a lot of non-trivial player input in the middle of the computation though.

Flag September 17, 2012 2:27 PM PDT
I was just intending to clarify SadisticMystic's misconception.
Flag September 17, 2012 2:30 PM PDT

Sep 17, 2012 -- 2:27PM, adeyke wrote:

I was just intending to clarify SadisticMystic's misconception.

I think he was referring to Alex's plan of blinking the shaman. in which case what he said is correct. you can't evolution in time to change the creature type when blinking.

Flag September 17, 2012 3:10 PM PDT
And that's what happens when I post without first getting the necessary understanding of the context. Sorry about that, and please disregard.
Flag September 17, 2012 4:34 PM PDT
What is the point of a computer made out of Magic cards? How would you do that? Can it even run Crysis?
Flag September 17, 2012 8:13 PM PDT

Sep 17, 2012 -- 4:34PM, Iam_IronMan wrote:

What is the point of a computer made out of Magic cards?

The fact that you can do it is cool.

Sep 17, 2012 -- 4:34PM, Iam_IronMan wrote:

Can it even run Crysis?

Yes. Isn't that kind of cool?

(Admittedly it'd run unbelievably slowly, but it could run it.)

Flag September 18, 2012 3:13 AM PDT

Sep 17, 2012 -- 7:38AM, SadisticMystic wrote:

Unfortunately, that isn't going to be extensible to anything beyond Shamans, since reentering a zone causes object modification to reset, and it's not even possible to keep re-hacking with Artificial Evolution because the ability has already triggered by the time it could be used, and it can't touch triggered abilities that are already on the stack.

Even making token copies of a Rage Forger doesn't work because layer-3 effects aren't copiable.

Sure, but that's fine. We just use Shamans as the creature type. You'll note that in the current machine where we need to refer to a creature which repeatedly leaves and re-enters the battlefield, I don't hack it, but instead hack everything else to refer to type Sphinx. As long as I don't need type Shaman to refer to anything else, that'll be okay.

Oh, unless what you're pointing out is that it'll be a problem because I need to be able to put +1/+1 counters on another category of creatures as well: if one half of the tape is Shamans, I still need a way to pump the other half. That is a valid problem. If only 's ability was triggered.

I think my current best option for eliminating all "may"s is something based around , where one half of the tape is one colour and the other half is a different colour, and when we step one direction we arrange for a player to discard (or with the only targetable land a ) and the other direction we arrange for a player to discard . The player/s in question are enchanted with , there's an in play, and there's to make the damage permanent. Then we use to put +1/+1 counters on both halves of the tape, and the burn spell (I guess doubled via ) to put two -1/-1 counters on the correct half. (Instead of doubling we could use , and .)

Flag September 18, 2012 10:02 AM PDT
if you use the hex and gale, make sure to have a set to black so hex only deals 1 damage.

well, two with furnace. but the point is to avoid it dealing 4.

Flag September 18, 2012 1:59 PM PDT

Sep 18, 2012 -- 10:02AM, razorborne wrote:

if you use the hex and gale, make sure to have a set to black so hex only deals 1 damage.

well, two with furnace. but the point is to avoid it dealing 4.

Flag September 18, 2012 3:38 PM PDT

Sep 18, 2012 -- 1:59PM, bay_falconer wrote:

Sep 18, 2012 -- 10:02AM, razorborne wrote:

if you use the hex and gale, make sure to have a set to black so hex only deals 1 damage.

well, two with furnace. but the point is to avoid it dealing 4.

His combo creates a computer. Yours does what? Wins a card game? *Applause.*

Flag September 18, 2012 4:10 PM PDT
Now, to throw in the so that we can achieve the internet...
Flag September 18, 2012 7:42 PM PDT

Sep 18, 2012 -- 3:38PM, CommanderJim wrote:

Sep 18, 2012 -- 1:59PM, bay_falconer wrote:

Sep 18, 2012 -- 10:02AM, razorborne wrote:

if you use the hex and gale, make sure to have a set to black so hex only deals 1 damage.

well, two with furnace. but the point is to avoid it dealing 4.

His combo creates a computer. Yours does what? Wins a card game? *Applause.*

True dat. One ends a game in three turns, the other one creates them its own damn self.

Flag September 19, 2012 4:22 PM PDT
So if you run MTGO on this, and then set up this situation on MTGO, you'd have Inception?
Flag September 19, 2012 4:36 PM PDT

Sep 19, 2012 -- 4:22PM, EyeHunter wrote:

So if you run MTGO on this, and then set up this situation on MTGO, you'd have Inception?

the slowest Inception ever.

Flag September 19, 2012 5:45 PM PDT

Sep 19, 2012 -- 4:36PM, razorborne wrote:

Sep 19, 2012 -- 4:22PM, EyeHunter wrote:

So if you run MTGO on this, and then set up this situation on MTGO, you'd have Inception?

the slowest Inception ever.

Yeah, DeCaprio would begin to blink before he woke up.

Flag September 21, 2012 4:21 PM PDT

Sep 19, 2012 -- 4:36PM, razorborne wrote:

Sep 19, 2012 -- 4:22PM, EyeHunter wrote:

So if you run MTGO on this, and then set up this situation on MTGO, you'd have Inception?

the slowest Inception ever.

Which, given that it's competing with the movie, is a pretty impressive feat :33.

Flag September 26, 2012 10:00 AM PDT
Okay, version 5 is online:

www.toothycat.net/~hologram/Turing/

I've fixed the universal Turing machine, changing it from the (2 state, 3 colour) one (which wasn't properly universal unless the tape is infinitely large and nonrepeating) to a (2 state, 18 colour) one which is widely accepted. I've also eliminated the fiddly ---- madness in favour of a much more sensible approach, involving and a wielding a

Meanwhile, I'm still plugging away at v6. looked promising at first, but its "players can't draw cards" proved annoying; but has a lot of promise. Rather than fiddling around with burn spells that only damage a selected subset of creatures, I think it'll work much more simply to hack , and use either or . along with let me make one player discard their burn spell and the other get to cast it. There are still a bunch of details to figure out, though, which have been proving rather fiddly and annoying. I'm pretty confident I'll get there.

And even if that approach doesn't pan out, Khoth has an outline of an astonishing alternative approach, which would even allow more than 2 states! And it's built on, of all things, , , and - I'm not making this up - :D
Flag September 26, 2012 1:05 PM PDT
This is all great work.

Once the "you may" is sorted i'd like to see a video of a game starting, drawing cards each turn and setting things up, then performing a basic but algorythmic calculation.
Flag September 26, 2012 2:32 PM PDT
in the cards section, you have both Slith and Siren marked as S1. FYI. also Blinkmoth and Bringer are both at times marked as B1.

Flag September 26, 2012 3:03 PM PDT
really cool. unfortunate upswing in "may" abilities with the archer and skitter, but a lot less fiddliness with mana so it's all good. and as far as I can tell you can still cut that down with a .

Flag September 26, 2012 3:39 PM PDT
Wasn't it confirmed that you can make an infinite combo with and on the field on a same turn? o_o"

You wouldn't be doing anything, just drawing cards. Probably would be good havng or on the field. Hell, add if you're worried of killing yourself in the process.
Flag September 26, 2012 4:10 PM PDT
That has nothing to do with the Turing Machine, and if a loop makes progress toward finishing the game (such as dealing damage to players or taking cards out of your library), it isn't really an unbounded loop, is it?
Flag September 26, 2012 4:21 PM PDT

Sep 26, 2012 -- 4:10PM, SadisticMystic wrote:

That has nothing to do with the Turing Machine, and if a loop makes progress toward finishing the game (such as dealing damage to players or taking cards out of your library), it isn't really an unbounded loop, is it?

There are several such infinite loops in Magic. / and / are two of the most exploitable ones.

Flag September 26, 2012 5:53 PM PDT

Sep 26, 2012 -- 4:21PM, bay_falconer wrote:

Sep 26, 2012 -- 4:10PM, SadisticMystic wrote:

That has nothing to do with the Turing Machine, and if a loop makes progress toward finishing the game (such as dealing damage to players or taking cards out of your library), it isn't really an unbounded loop, is it?

There are several such infinite loops in Magic. / and / are two of the most exploitable ones.

This creates loops that are impossible to tell if they're infinite or not.

Flag September 26, 2012 9:20 PM PDT

Sep 26, 2012 -- 3:39PM, richeyz wrote:

Wasn't it confirmed that you can make an infinite combo with and on the field on a same turn? o_o"

also, no.

Niv-Mizzet, the Firemind dealing damage doesn't trigger Niv-Mizzet, Dracogenius. it's not the same card.

Flag September 27, 2012 8:53 AM PDT

Sep 26, 2012 -- 3:03PM, razorborne wrote:

really cool. unfortunate upswing in "may" abilities with the archer and skitter, but a lot less fiddliness with mana so it's all good. and as far as I can tell you can still cut that down with a .

/ do remove one "may", but only at the cost of increasing complexity, because I'd have to double up the shrinkers and lose the elegant mirroring. I'll obviously avoid "may"s for version 6, but for the moment I think it's better to keep the Kazuul Warlord / Noxious Ghoul symmetry, for comprehensibility.

Thanks for pointing out the duplicate S1 / B1. Siren is S2 and Bringer is B2, I'd just transcribed it wrong.

Flag September 27, 2012 8:59 AM PDT

Sep 26, 2012 -- 1:05PM, alan2here wrote:

This is all great work.

Once the "you may" is sorted i'd like to see a video of a game starting, drawing cards each turn and setting things up, then performing a basic but algorythmic calculation.

Hahahaha. :D

I've tried a couple of times to run the simple version (the (2,3) machine) in MTGO. is a required 4of in each of the 4 decks to get things set up Unfortunately MTGO limits you to 2 hours (or 2.5 hours, maybe) per player even in casual games, and the game starts running pretty slowly once you have a board full of s and s. And MTGO's handling of isn't great: it only shows the changed version if the original creature type was in the singular on the source card! So s can be Evolved fine, but you have to remember which changes you've made to the s. And running with twenty or thirty permanent text-change effects seems to slow down the MTGO client quite a bit as well.

So I've not actually got as far as getting the machine completely set up on MTGO yet. I may give it another go at some point though.

Flag October 11, 2012 6:32 AM PDT

Hi all. Thought I'd let you know that I believe I have version 6 of the combo ready. This is the version with no "may" abilities anywhere: everything's completely forced once the combo is fully set up. I'm hoping that some of you might be up to reading through the combo checking it works and even offering suggestions for simplifying it.

The basic idea is fairly simple, and it turns out to make normal processing almost as quick as in v5, and changing state is even simpler than it was. Unfortunately, to handle running out of tape I've had to add an entire extra player, bringing the combo up to 5 players. I'm definitely looking for ways to reduce the number of players involved.

The setup of version 6 is as follows:

This time execution proceeds over multiple turns, one turn-cycle per step. The tape is controlled by Alex as before, with blue token creatures representing the tape to the left of the current head (the closest at 1/1, next-closest at 2/2, etc) and green tokens to the right. The tokens have one of eighteen creature types corresponding to what "colour" the space is. Like before, we use two sets of 18 s double-hacked by , one set phased out, all controlled by Alex.

But as well as those 36 phasing Reanimators, we also now have another set of 36 phasing s, all controlled by Cathy. This is because I'm using rather than to get non-optional +1/+1 counters, which makes it really fiddly to use "messenger" tokens under the tape player's control. Cathy's array of Reanimators make temporary tokens to control tape movement & state changes as I'll explain later.

(Granting all 72 Reanimators phasing without using token Auras is faintly fiddly, but perfectly doable. Details Show

and grant 8 x the number of players; another 4n; using , we can get another 8n from and ; and there are tricks with and to get as many more as we like.)

All 5 players have , empty library, and one card in hand. Graveyards can be as full as you like. There's a which forces each player to play their card on their turn, unless they've been forced to discard it by a trigger from ( to trigger off black creatures dying). The card is cast during their upkeep, goes to library rather than graveyard on resolution thanks to , and then gets drawn in their draw step.

The tokens on both halves of the tape are pumped up by , triggered by the new token arriving. To shrink one half by 2 (to net a shrink by 1 after cancelling out the pump from Cathars' Crusade), we either have Denzil cast or Emily cast . to black makes Kaervek's Hex only hit the green half of the tape, doubles the 1 damage from each burn spell to 2, and makes the damage permanent. We make sure the burn spells only damage one half of the tape by using a few s so Alex is the only legal target player for , and letting the leftwards Reanimators make blue tokens and the rightwards ones green tokens.

(I had hoped to use , but that runs afoul of 's "damage can't be prevented" line.)

So each turn cycle, either makes Denzil cast targeting Alex, shrinking the left half of the tape, and Emily doesn't get to cast because she was forced to discard it; or vice versa. We can also use to make Cathy either cast or discard , depending on whether we want a phase change or not. (Because each step is a different turn, Time and Tide plays the opposite role to v1-5: we cast it when we want to stay in the same state as before, because all the Reanimators phase at the start of Alex's turn anyway!)

When a token on the tape dies, that triggers Reanimators to make a new token for Alex; and also Cathy gets to make a temporary messenger token. This messenger token dies immediately to , and will in turn create another messenger token for either Denzil or Emily. Between these two tokens we get either one or two triggers of , making Denzil discard or Emily discard , and perhaps also Cathy discard .

I want processing to happen on Alex's turn, not on Denzil's or Emily's, because that could lead to getting two Turing steps in one cycle. So Alex has two to make all the tokens one point larger than they'd have to be to die when or resolve. I make them temporarily two points smaller on Alex's turn by having the spell that Alex casts off every turn be . So it's in Alex's upkeep that the smallest token actually dies, having got a -1/-1 counter in Denzil's or Emily's.

So this all handles normal movement and state changes very smoothly. Halting the machine is also easy, using . Unfortunately, noticing when we're out of tape is a whole lot harder.

This is what Bob does in the new version. He also has a Reanimator watching for any of the messenger tokens that are normally produced on Alex's turn, making him discard his card. If we're out of tape, then when Alex casts and nothing dies, Bob will fail to discard his card, and be forced to play it instead.

His card is , the only land to feature in the combo. It's forced to bounce itself; but first, a trigger resolves from a , controlled by Cathy and hacked with to make creatures of type Colour 1 of the tape. The Seed the Land token dies immediately, triggering machine execution just as if the tape had included a Colour 1 token at that point. Execution happens on Bob's turn rather than Alex's, but that doesn't matter: fortunately the order that triggers go on the stack doesn't affect much now things are spread across multiple turns.

Further choices are removed by giving everyone and/or having copies of hacked to all colours, and exiling all lands apart from Bob's Chancery in hand so nobody even has the opportunity to tap anything for mana.

----

So that's the proposed setup. I'll be writing this up for the website over the next week or so.

If anyone can see any bugs in the combo, please tell me. And if you've got any ideas for simplifying it, I'd love to hear that too.

I'd especially like to make the running-out-of-tape handling not need a whole other player, but it's pretty fiddly: there aren't many things that trigger on "whenever a creature doesn't die".

It's somewhat complicated by the way that I'm also avoiding ever letting two (or more) abilities trigger for the same player for the same event: after all, then the player would have to make a choice (which order to put them on the stack), and we can't have that, can we? This makes it rather fiddly because does have a habit of triggering off all the same things I want to notice. Any ETB triggered abilities in the machine basically can't be under Alex's control, because then they'd need ordering relative to Cathars' Crusade's trigger.

There are some possible changes that seem like simplifications, but that would require different creature types when writing a Colour12 space to the left vs writing a Colour12 space to the right. But that'd require a whole array of hacked s, at least 18 of them and probably 36, and I'm quite glad to have got away from the hordes of Crusades: the current version of v6 doesn't include any at all!

I've considered trying to combine two of the spellcasting players into one using , but conditionally discarding the second card is very hard and the only player who unconditionally casts a spell also has preventing them from using to discard the first one. (But perhaps something could be arranged with or ?)

Flag October 11, 2012 11:46 AM PDT
one problem: how does the machine stop Bob from just playing the Chancery? it makes him discard before his turn, but then he draws it and passes through his main phase without playing it. that is an active decision to not act he has to make every turn, unlike every other aspect where action is impossible. the only way I can see to prevent it is to give one player and but you're currently using each player's upkeep in some way so that would require an additional sixth player.

that's not true, I can think of another way (replace the masks with s and have someone who plays every turn on Bob) but that still requires Felix.

I actually just had an idea but it's complicated and I need to run, I'll explain when I get back.

Flag October 11, 2012 11:47 AM PDT
Bob has the ability to manually play his bounceland if he so desires, creating an extra (and possibly erroneous) tape step. That's probably a bug. You can counteract this with plus ten lands that have no effect, like the cycle.

Creating extra copies of the phasing Auras is really quite simple: play one of the s choosing not to copy anything, animate it, and then a regular old can chain through its copy effect and choose an Aura to copy.

Also, with Painter's Servant on black, a single Light of Day is sufficient to stop all attacks, and compactness is at least worth something when the combo is taking so many cards as it is. Just make sure you don't accidentally kill the Servant.
Flag October 11, 2012 1:18 PM PDT

Oct 11, 2012 -- 11:47AM, SadisticMystic wrote:

Bob has the ability to manually play his bounceland if he so desires, creating an extra (and possibly erroneous) tape step. That's probably a bug. You can counteract this with plus ten lands that have no effect, like the cycle.

this is way simpler than my idea. my idea involved giving someone and then giving Bob a , more rotlung reanimators that can remake the saproling, and some way to kill the saproling each turn between when the chancery enters the battlefield and when its trigger resolves, but the limited resources way is far simpler.

Flag October 12, 2012 3:27 AM PDT

Good catch all! I was tossing up a few different ideas for Bob's card. I thought Seed the Land + a bounceland was better than the other options, but I was definitely wrong.

Let's make it a in hand, plus a hacked to make Colour1 tokens. will catch the dying creature just like the instants and sorceries. (In fact given there's an around, could just as easily be a simple .)

Good catch on just needing one given that we've already got a out.

I guess I can use simple s of an uncopied . There are a handful of Clones I can use, but now that we're spread across multiple turns, a lot of them disqualify themselves: and are no good, and nor are or .

So I wanted a solution that'd definitely give me enough Clones even if I got the number of players down to 4 (and remembering I need some Clones to make the 72 nontoken Reanimators). Being able to use as a phasing Aura is kinda satisfying.

But there are probably enough Clones available: I can still use , , , , and heh, even if I bring along a for a moment. So that is probably enough without doing silly Transreliquat tricks. As you say, the combo's complicated enough already.

Flag October 12, 2012 12:41 PM PDT
why bother with the germination? why not just use, like, ? your triggers don't have to be tokens, do they?

Flag October 12, 2012 1:10 PM PDT
there seems to be a little information missing. how do Cathy's messenger tokens create tokens for Denzil and Emily? do they also have s? if so that should be mentioned.

also if you wanted to you could replace with . doesn't really accomplish anything though.

Flag October 12, 2012 3:28 PM PDT
Darkest Hour doesn't work because it overwrites colors, rather than adding to them, so that it won't be possible to distinguish left and right with different colors.
Flag October 13, 2012 12:53 PM PDT

Oct 12, 2012 -- 12:41PM, razorborne wrote:

why bother with the germination? why not just use, like, ? your triggers don't have to be tokens, do they?

Ha. I guess that'd work, if Colour1 is Ape. I was thinking I wouldn't be able to hack a creature spell to the correct type, but yeah, I can just find a creature of the correct type that'll die to . Nice thought

Oct 12, 2012 -- 1:10PM, razorborne wrote:

there seems to be a little information missing. how do Cathy's messenger tokens create tokens for Denzil and Emily? do they also have s? if so that should be mentioned.

Yeah, that was the plan. I'll be sure to include that detail on the website writeup.

Which it sounds like ought to be good to go. Excellent - thanks all.

Flag October 13, 2012 3:10 PM PDT

Oct 13, 2012 -- 12:53PM, alextfish wrote:

Oct 12, 2012 -- 12:41PM, razorborne wrote:

why bother with the germination? why not just use, like, ? your triggers don't have to be tokens, do they?

Ha. I guess that'd work, if Colour1 is Ape. I was thinking I wouldn't be able to hack a creature spell to the correct type, but yeah, I can just find a creature of the correct type that'll die to . Nice thought

I was assuming you'd use the same types as v5, but no matter what you use most creature types have at least one member with 2 or less toughness.

Flag November 8, 2012 12:49 PM PST
Could the s be granted phasing by set to Forest, with a in play?
Flag November 9, 2012 11:57 AM PST

Nov 8, 2012 -- 12:49PM, eswald wrote:

Could the s be granted phasing by set to Forest, with a in play?

On second thought, that requires more work to remove the ability to tap them for mana.  set to Saproling, for example, or a hacked .

Flag November 9, 2012 2:51 PM PST

Nov 8, 2012 -- 12:49PM, eswald wrote:

Could the s be granted phasing by set to Forest, with a in play?

With or , yes, yes it could.

Flag November 9, 2012 2:58 PM PST
I have a combo you could use to make your s. With a in play and a on top of your graveyard, that comes into play under your controll will be a . Then just put a on top of the yard. The you're already using protects them, and they are just as . And because they are not tokens they work just fine with phasing.

This is because uses a a text changing effect to gain the 's attributes. Then when another creature enters the battlefield the replacement effect from the essence applies to the copiable attributes in layer one. Making the creature a shapeshifter, which then gets its own text changing effect.

Flag November 9, 2012 5:23 PM PST
A simple will shut down the ability to tap creature-lands for mana, without requiring prearrangement for them all to be tapped, and since the whole point of the combo is to be mandatory, shutting down activated abilities (which are all discretionary) isn't such a bad idea anyway. It would take care of things like the ": Discard a card" on Volrath's Shapeshifter too.

The tricky part is arranging it so the Reanimators are all Saprolings (and thus forests, and thus phasing) but no other creatures are, because you don't want anything else suddenly disappearing. The easiest way is probably a hacked , which can go away once setup is complete.
Flag November 9, 2012 7:41 PM PST

Nov 9, 2012 -- 5:23PM, SadisticMystic wrote:

A simple will shut down the ability to tap creature-lands for mana, without requiring prearrangement for them all to be tapped, and since the whole point of the combo is to be mandatory, shutting down activated abilities (which are all discretionary) isn't such a bad idea anyway. It would take care of things like the ": Discard a card" on Volrath's Shapeshifter too.

The tricky part is arranging it so the Reanimators are all Saprolings (and thus forests, and thus phasing) but no other creatures are, because you don't want anything else suddenly disappearing. The easiest way is probably a hacked , which can go away once setup is complete.

or which can sit there with the totem.

Flag February 1, 2013 10:06 AM PST
made me think of this again, particularly in conjunction with , for arbitrarily many forced attacks.  Granted, you need a triggered way to flicker Aurelia; perhaps.  is so close to being right for the job...

Then again, version 6 seems to have things under control, and has removed the that required all that combat in the first place.  It might be interesting to remove the requirement by switching the attacked player through some sort of exile or control-switching effect, but that requires rewriting the whole engine.  I'm not entirely sure it would even work yet.

I also noticed as a single-turn way to force-cast a particular spell, but the only good way to avoid problems with the user's choice of which spell to cast first precludes using it to cast another copy of itself.
Flag May 4, 2013 3:51 AM PDT
There are two problems in the arrangement. One is that you cannot have Bereavement changed to black because of the Painter's Servant making everything black; change it to red or white instead. The other problem is that Furnace of Rath doubles the damage from Æther Flash too, which is too much; that can be solved by adding two more Glorious Anthems, or you can replace all four with a .

Instead of Cathars' Crusade, you can use enchanted with a colour-changed that has a later timestamp than Painter's Servant, an attacking requirement, and . This allows using tokens of some other types to mark the ends of the tape which set off triggers to continue computation as appropriate and also to re-create them, removing Bob.
Flag May 4, 2013 4:53 AM PDT
Bereavement is supposed to hit black and trigger upon anything dying. Furnace of Rath is a wrinkle, but one that can easily be fixed by changing it to , again hacked to black because everything is black. Unlike Furance of Rath, Sulfuric Vapors only works on spells dealing damage, so it will increase the damage from Kaervek's Hex or Ember Gale without touching the triggered ability on AEther Flash.