The Tetris guidelines Random Generator is apparently simple.

[colour_thief]

In games adhering to the official Tetris Guidelines, most notably TDS, the randomizer is known to not be purely random. In fact, the randomizer's rules are quite simple:


Give the player each of the 7 tetrominoes, in a random order.

Give the player each of the 7 tetrominoes, in a random order.

Give the player each of the 7 tetrominoes, in a random order.

...

and so on


So, this explains why the randomizer is good enough to give you fairly consistent I pieces, yet bad enough to give you strings like SZSZ.


This thread has 2 purposes. The first is to discuss the implications of this randomizer on strategy. For example, getting all T-spin singles (which has the greatest return of points per line) would require 40% of the pieces to be T pieces. Obviously this is impossible with this randomizer. What then might the optimal strategy be? Also, if you've got holes in VS that require 2 T pieces or 2 I pieces to repair (and your Hold is empty), then unless you think you can survive 7 pieces on average, you should consider cutting your losses and making a controlled hole instead of waiting and making a potentially worse one.


The second purpose of this thread is to document which games use this randomizer. Only games made after the formation of TTC (1996 and later) need to be considered. Below is a partial list. If you guys could test any versions you have access to, that would be great.


Games that use the guideline randomizer:
-Tetris Battle
-Tetris Deluxe
-Tetris DS
-Tetris The Grand Master ACE
-Tetris Worlds

Games that DO NOT use the guidelines randomizer:
-Tetris DX
-Tetris The Grand Master
-Tetris The Grand Master 2
-Tetris The Grand Master 3
-The New Tetris


To quickly see if you have a post-1996 game to check, please consult this list:

http://www.tetrisconcept.com/tetriswiki/Games (http://www.tetrisconcept.net/forum/../tetriswiki/Games)

[caffeine]

will check deluxe soon...

[Sully]

Wow. It was brought to my attention a few weeks ago that (in TDS) the first 7 pieces were one of each at random, but I never realized that this pattern continued for the entire game.


This may be the missing bit of info that I needed to be able to compete with HoLiC.

[deepdorp]

tetris worlds (i can only vouch for the PS2 version) does use this system also, but with one exception: square mode has a more classic random system. This exception is pretty much necessary for square mode, mostly for building the gold blocks, but also for silvers.

[colour_thief]

Thanks, I've updated the list.


People, check anything you can. Even those handheld LCD versions.

[deepdorp]

here's another:

the new tetris (n64) does not use the convention you described. Again, this is probably due to the gold/silver block system used in tnt.

I checked some TGM3 videos (both rule types) and they don't use this system.

[colour_thief]

Oops. Yeah I knew that one, should have included it.

[caffeine]

deluxe-yes

dx-no

nes-no

gb-no

[tepples]

(title nit: The randomizer is simple but wallkick is not.)


In the guideline randomizer as you describe it, there are 5,040 possibilities for each sequence of 7. This may even make it mathematically cheaper to generate sets of pieces on really limited hardware (e.g. 8-bit embedded systems).


How does the randomizer in The Next Tetris (PS1) and Tetris Worlds Sticky decide when and how to generate a multi-color piece?

[colour_thief]

(title nit: The randomizer is simple but wallkick is not.)


Yeah, that's a goof on my part. I intended to put the word randomizer in there but evidently I did not.


EDIT

Cool I can edit the title.

And... quotes are still broken argh.

[caffeine]

yeah, they said the new version, which i installed yesterday, would fix the quotes. i guess it doesn't.

[Sully]

T.T

[Phydeaux]

Mmm. Time to turn off guest posting. Had to do that in my kids' forum, too.

[tepples]

Or do what nesdev.com's phpBB board has done: a separate forum for guest posting, which is useful as a test forum or to report problems with the phpBB software.

[tepples]

Is there an administrator on duty who can grant some emergency moderator powers to clean this up? I'm respected on gbadev.org and nesdev.com.

[colour_thief]

For some reason they really like this topic. I swear I've deleted 10 spam messages, all from this topic. I usually catch them faster... Sorry guys.


I have a good excuse though. I was at a gaming tournament playing TDS. Video to come...

[kbr420]

Hi,


Let me start off by introducing myself. I work for BPS, sole owner of Tetris. If you guys have any questions or comments, please feel free to ask.


Speaking about the randomizer, known as the "Random Generator", all new games that have been released within the past 5 or 6 years will have the system implemented. Any game that is being released without it, usually is a remake of an older generation Tetris product. But for now, you will see that all current and upcoming games will have 7 Tetriminos in the Random Generator.


TGM3 is an excellent game. This game has both the Random Generator and the older non-standard system of spitting out Tetriminos.


I would like some feedback from all of you. Do you like the Random Generator with 7 Tetriminos? Would you rather have more in the system (i.e. 14)?

Wow, seems like we have a VIP on the forum...

I like the random generator for Tetris DS. Maybe 14 pieces would be better, but I don't think that it affects gameplay in a huge way. I like the 7 pieces generator because I can mentally predict how soon I will get a specific piece.

The 7 piece generator is also fairer online. A completely random generator might leave one player without an I piece for 20 pieces or so.

VIP? http://www.tetrisconcept.net/forum/images/smilies/icon_biggrin.gif ....yeah right!

I agree with you on the 7 piece system currently. There are talks about changing it. But with the feedback I get from the end users, it could be really helpful in making the decision.

[kbr420]

VIP? http://www.tetrisconcept.net/forum/images/smilies/icon_biggrin.gif ....yeah right!
I agree with you on the 7 piece system currently. There are talks about changing it. But with the feedback I get from the end users, it could be really helpful in making the decision.


that's me btw. sorry i forgot to log in.

[tepples]

Speaking about the randomizer, known as the "Random Generator", all new games that have been released within the past 5 or 6 years will have the system implemented. Any game that is being released without it, usually is a remake of an older generation Tetris product.
Either that, or it's a variant mode of play, such as Square Tetris. Because having multiple identical "Tetriminos" in a row is an advantage in Square Tetris, I've noticed that The New Tetris and Square mode of Tetris Worlds don't use the Random Generator.

I would like some feedback from all of you. Do you like the Random Generator with 7 Tetriminos?
Yes. It's a different play-style, and scoring isn't really comparable between "Memoryless" mode (classic rand()%7) and "Random Generator" (permutation at a time) mode.

A completely random generator might leave one player without an I piece for 20 pieces or so.

True, "Memoryless" results in longer maximum runs of one "Tetrimino", but if all players receive the same sequence (from the same seed (http://en.wikipedia.org/wiki/Random_seed)) as was the case in Tetris & Dr. Mario for Super NES, it becomes more fair.


But the Random Generator has one weakness: Games that use it can be played deterministically (http://www.tetrisconcept.net/forum/../tetriswiki/Playing_forever), making it easier to construct a bot that can toss out multiple Tetrises in a row obscenely quickly. And it'd also be useful to have a standardized name for this behavior that's more specific than "Random Generator". (EA calls it "Random Tetrimino Bag" (http://www.eamobile.com/Web/Catalog/US/en/game/mobile/ProductDetailOverviewView/product-24171).)

[K]

Hello mister "kbr420" :

what is your "exact function" on BPS to want feedback about this randomizer ?

you lives in HAWAI ?


sorry but i'm (and surely not the only one) skeptic about "VIP" guy claiming working for BPS coming here for collecting feedback about "the randomizer"...


it would be really great if we were able to discuss about Technicals choice on TETRIS guideline, but please be more persuasive on your working job description...


thanks.

[kbr420]

Hello mister "kbr420" :
what is your "exact function" on BPS to want feedback about this randomizer ?
you lives in HAWAI ?

sorry but i'm (and surely not the only one) skeptic about "VIP" guy claiming working for BPS coming here for collecting feedback about "the randomizer"...

it would be really great if we were able to discuss about Technicals choice on TETRIS guideline, but please be more persuasive on your working job description...

thanks.


I'm sorry, I do not want to post any personal information regarding my job title. But, yes I do live in Hawaii.


It is more than understandable for you to be skeptical about my claims, but they are true, take it as that. You can ask me any question regarding Tetris and the mechanics of it, but I cannot disclose anything from our Tetris Design Document. This document is for our licensees to have for development and not open to the general public.


The reason why I am asking for feedback regarding the Random Generator which is what IT IS CALLED, is because there are talks about changing the system. I personally do not want the change to a greater amount of Tetriminos in it. I like it at 7. No more, no less.


BTW, in the SRS (Super Rotation) images on this website, the rotation point for the I-Tetrimino is the second to the left block, standardly known as a Mino....tepples, you did a good job in describing the aspects of the game!

[tepples]

Agreed. I don't ask for trade secrets here or on forum.gbadev.org. But phoxinus (http://en.wikipedia.org/wiki/Eurasian_minnow)?

[colour_thief]

TGM3 is an excellent game. This game has both the Random Generator and the older non-standard system of spitting out Tetriminos.

If I understand you properly here, I believe you are misinformed. I know for certain that the main modes (Master and Shirase) use neither the Random Generator nor the older chaotic system. In fact, I have performed a statistical analysis on the game which strongly suggests its generator follows these rules:

-the game keeps a history of the previous 4 pieces
-if the game generates a piece found in this history it will reroll
-the game will reroll up to 4 times before giving up

Given these rules, the probabilities of various phenomenon match those found in TGM3 piece sequences very closely. If you're interested I've got a half written description of my analysis I could finish and share. It's fairly long though.

I would like some feedback from all of you. Do you like the Random Generator with 7 Tetriminos?


The bag method is definitely leagues better than the common modulo 7 approach. However, there are "seams" where the "bags" connect, if you follow the metaphor. The player is fairly often dealt strings of SZSZ at this point, and it's not uncommon to be starved of the I mino for 12 pieces. It makes for a bumpy ride, with each seam potentially throwing a nasty sequence at the player (Hold doesn't help much against SZSZ) or throwing too good a sequence at the player (II) that will starve him from that essential piece for a while.


The TGM style generator described above is more consistent. This is essential in the arcade when you are paying for every game and demand consistent value for your 100 Yen. I think it should apply in consumer games also, because I like to get consistent value out of my free time. I realise that consistent doesn't necessarily mean better. Taken to an extreme, you would get boring piece sequences that are far too predictable. In my opinion though, the TGM piece randomizer is well balanced and does not go too far. It's smooth yet unpredictable.


Using 14 pieces instead of 7 for the Random Generator would introduce more chaos than even the current rules, making it more similar to the classic games. In my opinion this is a step in the wrong direction, or at least a step away from my personal preferences.


Just so you don't get the wrong idea, I am also critical of the TGM approach. My ideal method would use a different technique to achieve all the benefits of both modern methods without any of the drawbacks. But this post is getting long and off topic now so I'll stop. http://www.tetrisconcept.net/forum/images/smilies/icon_smile.gif

[tepples]

-the game keeps a history of the previous 4 pieces
-if the game generates a piece found in this history it will reroll
-the game will reroll up to 4 times before giving up
Equivalently, the game chooses one of the front three, adds it to the next piece queue, and then moves it to the back of the bag.

However, there are "seams" where the "bags" connect, if you follow the metaphor. The player is fairly often dealt strings of SZSZ at this point
If all 5,040 bags are equally probable, then the odds of getting a bag ending in SZ are 1 in 42; the odds of getting a bag ending in either SZ or ZS are 1 in 21. Therefore, the odds of a given seam being four snakes (SZSZ, SZZS, ZSSZ, or ZSZS) are 1 in 21*21 = 1 in 441. A typical game of 40-line B-type will have about 105 Tetriminos, or 15 bags; you can expect four snakes in a row in roughly 1 out of 441/15=29.4 games.

and it's not uncommon to be starved of the I mino for 12 pieces.
One out of 49 seams will have I, twelve others, I. That's what the Hold Piece is for.

(One thing: Why hold "piece", next "piece", and ghost "piece" when the rest of the user manual uses the term Tetrimino?)

(Hold doesn't help much against SZSZ)
Hold doesn't help you against SZSZ. The point is to look at the next pieces (and official games seem to show at least 3 nowadays), and if you see a lot of snakes on the plane, grab a T and hold it.

or throwing too good a sequence at the player (II) that will starve him from that essential piece for a while.
II means use the hold piece, or start building for an L triple or a T-spin double.

The TGM style generator described above is more consistent. This is essential in the arcade when you are paying for every game
Either that, or the game supports a mode similar to Nintendo's PlayChoice (http://en.wikipedia.org/wiki/PlayChoice) in which the player rents the machine for 5 minutes and plays as many games of B-type as fit into that time period. A 55tpm player could fit at least 3 games of 40-line B-type into that time.

In my opinion though, the TGM piece randomizer is well balanced and does not go too far. It's smooth yet unpredictable.

Imagine an inlet pipe on your tetrion, right next to the bottom of the next piece queue. Connect a memoryless randomizer, TGM move-to-back randomizer, or Random Generator to that pipe.

[colour_thief]

I think you were a little too pedantic in your reply... 4 of SZ in a row is the worst case. More generally I think 3 of SZ in a row is also unfair. And if your Hold slot is already filled with an I mino and you get II they're wasted on you.


I personally think it's a cop-out to say that Hold will solve these difficulties. It isn't used any less when you don't have to worry about compensating for unfavourable sequences. The function of Hold simply shifts to higher level strategies. Instead of thinking "how do I deal with this incoming chaos" the player gets to more often think "how can I rearrange this sequence to get Tetrises/T-Spins/nothing stacked above where I'm about to open a hole."


To a certain extent we're always playing for that lucky optimal sequence anyways, and a generator with a constant history size just saves the player time and keeps things fair.

[Caithness]

I think moving in the direction you describe would make the game more boring, CT. To me Tetris has always been about finding the best way to deal with difficult situations, and if you eliminate or drastically reduce the number of times those situations occur, you take out a lot of the fun.

[Tarto]

I personally like the 7-piece generator, I think it's a good tradeoff between chaos and consistency.


Extending the "size" of the randomizer would add randomness to the game and, in my opinion, lead to less significant rankings.

I doubt the validity of asking people what algorithms are good or bad, without giving them a chance to actually playtest an implementation of said algorithms.


Game design is an iterative process. Good design only emerges out of repeated cycles of prototyping, testing, and evaluation. (As described in countless game design documents, notably Salen & Zimmerman's "Rules of Play.") It is impossible to fully grasp the implications of any design decision without actual prototyping and playtesting, as there are always consequences that affect play in a way that was unforeseen with mere simulation in the mind.


I don't think everyone who replied had actually played on a 14-bag randomizer or a move-to-back randomizer. Asking for input about algorithms on people without actual experience of said algorithms does little good, aside from strengthening the status quo, which people have actual first-hand experience with.


Therefore, if one was to solicit input for this decision, I would ask them to supply the respondents with functional prototypes implementing each algorithm.

[tepples]

I view open-source fan games as such prototypes. But unfortunately, The Tetris Company and its law firm are again projecting (http://insignificantthoughts.com/2006/07/10/tetris-company-picks-quinn/default.htm) an image that a game's functionality itself can be copyrighted (however the US Copyright Office doesn't agree (http://www.copyright.gov/fls/fl108.html)) and that fan games infringe TTC's copyright even if they do not infringe the Tetris trademark.

[colour_thief]

I agree with guest above, in that the average user's input is pretty meaningless without actually playing using a particular algorithm.


Along those lines, I would caution you Caithness to perhaps not prematurely dismiss constant history size algorithms as boring. After all, half the time the Random Generator is less predictable and half the time it is more predictable. If you play some TGM or watch the movies you will no doubt encounter clever puzzles in the gameplay, regularly.