Tetris
Webpages concerning "Tetris"
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Wikipedia-Article "Tetris"
| Tetris | |
|---|---|
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| Developer(s) | Various |
| Publisher(s) | Various |
| Designer(s) | Alexey Pajitnov |
| Engine | {{{engine}}} |
| Latest version | {{{version}}} |
| Release date(s) | 1985 |
| Genre | Puzzle |
| Mode(s) | Single player, multiplayer |
| Rating(s) | {{{ratings}}} |
| Platform(s) | Over 200 |
| Media | {{{media}}} |
| System requirements | {{{requirements}}} |
| Input | {{{input}}} |
Tetris is a puzzle game invented by Alexey Pajitnov (last name sometimes transliterated Pazhitnov) in 1985, while he was working for the Academy of Sciences in Moscow, Russia. Pajitnov has cited pentominoes as a source of inspiration for the game.
The game (or one of its many variants) is available for nearly every video game console and computer operating system, as well as on devices such as graphing calculators, mobile phones, and PDAs. Tetris has even appeared as part of an art exhibition on the side of Brown University's 14-story Sciences Library [1]. The game first gained mainstream exposure and popularity in the late 1980s beginning in 1988. Tetris consistently appears on lists of the greatest video games of all time; it is believed to be the best selling game ever, due to its wide availability on almost every modern computer and game system made.
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The game
Seven randomly rendered tetrominoes or tetrads - shapes composed of four blocks each - fall down the playing field. The object of the game is to manipulate these tetrominoes with the aim of creating a horizontal line of blocks without gaps. When such a line is created, it disappears, and the blocks above (if any) fall. As the game progresses, the tetrominoes fall faster, and the game ends when the stack of Tetrominoes reaches the top of the playing field.
The seven rendered tetrominoes in Tetris are referred to as I, T, O, L, J, S, and Z. All are capable of single and double clears. I, L, and J are able to clear triples. Only the I tetromino has the capacity to clear four lines simultaneously, and this clear is referred to as a "tetris."
Gravity
When a row of blocks is cleared and removed, the stacks of blocks above it fall. Traditional versions of Tetris move the stacks of blocks down by a distance exactly equal to the height of the cleared rows below them. Unlike Newtonian gravity, blocks may be left floating above gaps. This behavior is known as "naive gravity."
Some variants implement a different algorithm that uses a flood fill to segment the playfield into connected regions and then makes each region fall individually, in parallel, until it touches the region at the bottom of the playfield. This opens up additional "chain-reaction" tactics involving blocks cascading to fill additional lines, which may be awarded as more valuable clears.
History and legal issues
Tetris has been embroiled in a strangely large number of legal battles since its inception. In June 1985, Alexey Pajitnov created Tetris on an Electronica 60 while working for the Academy of Sciences in Moscow. He created it at their Computer Center, and Vadim Gerasimov ported it to the IBM PC.
From there, the game exploded into popularity, and began spreading all around Moscow. (This version was available on Vadim Gerasimov's web site, but the Tetris Company used the DMCA to force Gerasimov to remove it.)
The IBM PC version eventually made its way to Budapest, Hungary, where it was ported to various platforms and was "discovered" by a British software house named Andromeda. They attempted to contact Pajitnov to secure the rights for the PC version, but before the deal was firmly settled, they had already sold the rights to Spectrum Holobyte. After failing to settle the deal with Pajitnov, Andromeda attempted to license it from the Hungarian programmers instead.
Meanwhile, before any legal rights were settled, the Spectrum HoloByte IBM PC version of Tetris was released in the United States in 1986. The game's popularity was tremendous, and many players were instantly hooked—it was a software blockbuster.
The details of the licensing issues were uncertain by this point, but in 1987 Andromeda managed to obtain copyright licensing for the IBM PC version and any other home computer system.
By 1988, the Soviet government began to market the rights to Tetris through an organization called Elektronorgtechnica, or "Elorg" for short. By this time Elorg and Pajitnov had still seen no money from Andromeda, and yet Andromeda was licensing and sub-licensing rights that they themselves didn't even have.
By 1989, half a dozen different companies claimed rights to create and distribute the Tetris software for home computers, game consoles, and handheld systems. Elorg, meanwhile, held that none of the companies were legally entitled to produce an arcade version, and promptly signed those rights over to Atari Games, while it signed console and handheld rights over to Nintendo.
Tengen (the console software division of Atari Games), regardless, applied for copyright for their tetromino game for the Nintendo Entertainment System, loosely based on the arcade version, and proceeded to market and distribute it under the name TETЯIS (with faux Cyrillic typography incorporating the Cyrillic letter Ya), disrespecting both Nintendo's and Elorg's rights to the name. Many people think that the Tengen version is a more playable port than the Nintendo version.
After only a few (very popular) months on the shelf, the courts ruled that Nintendo had the rights to Tetris on home game systems, and Tengen's TETЯIS game was recalled, having sold only about 50,000 copies.
Nintendo released their version of Tetris for both the Famicom and the Game Boy (oddly though, the Game Boy version was developed by Bullet-Proof Software, Inc., despite Nintendo's license to the game) and sold more than three million copies; most players considered Nintendo's NES version inferior because it lacked the side-by-side simultaneous play of Tengen's version, but Nintendo's Game Boy Tetris became arguably the most well-known version of Tetris. The lawsuits between Tengen and Nintendo over the Famicom/NES version carried on until 1993.
Pajitnov himself made very little money from the deal, however, even though Nintendo was able to profit from the game handsomely.
In 1996, he and Henk Rogers formed The Tetris Company LLC and Blue Planet Software in an effort to get royalties from the Tetris brand, with good success on game consoles but very little on the PC front. Tetris is a registered trademark of The Tetris Company LLC ("TTC"). TTC has licensed the Tetris mark to a number of companies, but the legality of tetromino games that do not use the Tetris name has not been decided in court.
According to circulars available from the United States Library of Congress, a game cannot be copyrighted (only patented), which refutes much of TTC's copyright claims on the game, leaving the trademark on Tetris as TTC's most significant claim on any government-granted monopoly.
TTC no longer seems to pursue "clones" of the game under such names as:
- Quadra (http://quadra.sourceforge.net/)
- KSirtet (http://ksirtet.sourceforge.net/)
- Cowtris (http://nonsensesoftware.com/cowtris.html)
Scoring formula
The scoring formula for the majority of implementations of Tetris is built on the belief that more difficult line clears should be awarded more points. In Nintendo's implementations on the NES, Game Boy, and SNES, the four possible line clears are as follows:
- Single = (level+1)*40 one line is cleared.
- Double = (level+1)*100 two lines are simultaneously cleared.
- Triple = (level+1)*300 three lines are simultaneously cleared.
- Tetris = (level+1)*1200 four lines are simultaneously cleared.
| Level | 00 | 01 | 02 | 03 | 04 | 05 | 06 | 07 | 08 | 09 | 10 |
| Single | 40 | 80 | 120 | 160 | 200 | 240 | 280 | 320 | 360 | 400 | 440 |
| Double | 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900 | 1000 | 1100 |
| Triple | 300 | 600 | 900 | 1200 | 1500 | 1800 | 2100 | 2400 | 2700 | 3000 | 3300 |
| Tetris | 1200 | 2400 | 3600 | 4800 | 6000 | 7200 | 8400 | 9600 | 10800 | 12000 | 13200 |
On most implementations, players may press a button to accelerate the current piece's descent, rather than waiting for it to fall. When a player locks a piece in this way, many such versions award a number of points based on the height the piece fell before locking. If a piece is manually dropped x lines and locked before the button is released, these versions will typically award either x points, or (level + 1)*x points.
Modes of Play and Feature Deviations
Tetris has been subject to many changes throughout releases since the 80s. It is difficult to place a standard on the game, as newer releases frequently progress it either to make the game better or to keep players interested. Newer Tetris games have made the trend of pace rather than endurance. Older releases such as Gameboy or NES Tetris offer records according to points. Since the meter for points is set to only a certain number of digits, these game's records can be maxed out by an experienced player. The next big Gameboy release after Tetris, Tetris DX, in marathon mode — comparable to mode A in previous releases — allowed an additional digit for the point meter. Even so, players still maxed it to 9,999,999 after hours of play. For The New Tetris, world record competitors have spent over 12 hours playing the same game [2]. It is probably for this reason of seemingly everlasting play that in both Tetris DX and The New Tetris, the new modes sprint and ultra were added. These modes require the player to act under a timer — either to gain the most lines or points in that time. Recent releases like Tetris Worlds did away completely with point records. This particular game made records by how fast a certain number of lines could be cleared depending on the level. A drawback of this deviation, along with some other newer features, is that many traditional players rejected these advances all together. Critics of Tetris Worlds said it was broken due to how a piece is able to hover over the bottom for as long as a player needs [3]; although, players of the game generally do not mind this feature because exploiting it will only hinder play, which is unfavorable to making a record time. Tetris LLC has been juggling different features with different modes of play in past years trying to satisfy traditional and newer players alike.
There are many different modes of play added in recent years. Modes appearing in more than one major release include: classic marathon (game A), sprint (otherwise game B or 40 lines), ultra, square, and cascade.
The field dimension of Tetris is perhaps the least deviated among releases, with the exception of some releases on handheld platforms with small screens. It is almost always 10 blocks wide by 20 blocks high. However, the original Tetris for Game Boy is a major exception with 10 by 18. The field height was probably decreased to fit within the Game Boy screen. As a result, Tetris for Game Boy was more difficult compared to its NES counterpart. While players of Tetris for NES have reached 999,999 points [4], no such verified record exists on Game Boy Tetris. Although, it is fair to add that Game Boy Tetris also is subject to faster speeds at lower levels.
Blocks spawn traditionally in center most columns horizontally at topmost and second topmost row. Where: long block occupies columns 4, 5, 6, and 7. square block occupies columns 5 and 6. remaining 5 blocks occupy either columns 4, 5, and 6; or columns 5, 6, and 7.
Levels increment generally once every 10 lines in traditional games. While in some newer games such as Tetris Worlds, the number of lines required vary upon each new level. The fall speed also varies, but is usually no more than 20ms shaved off of each step for each coming level. For example, NES Tetris operating at 60fps and at level 0, a piece falls one step every 48 frames. While at level 19, a piece falls one step every 2 frames. There is an approximate 16ms decrease every level. Level increments will either terminate at a certain point (Gameboy Tetris will top off at level 20) or will increase forever yet not increase in speed after a certain point. NES Tetris will level up in until the speed of level 29 (due to frame restrictions, pieces are not capable of dropping faster than this), but tool-assisted emulation will show that the level indicator will increase infinitely-- eventually glitching the meter so that it must use hex values. Modern games such as Tetris: the Grandmaster or Tetris Worlds, at their highest levels, opt to drop a piece more than once per frame. Pieces will appear to reach the bottom as soon as they spawn. As a result, a hover or slide feature is often implemented into these games to help deal with an otherwise unplayable fall speed. In some games, the hover time is regenerated after a pieces is moved or rotated.
Soft drops were first implemented in Nintendo releases of Tetris so that pieces would be able to drop faster while not lock as to slide into gaps. The other option is hard dropping, which is mainly featured in PC Tetris games such as Microsoft Tetris. Here, a piece falls and locks in one frame. Newer Tetris games feature both options.
Single rotation is an older restriction that has since been ruled out in nearly every new official release by the favor of dual rotation, which uses two buttons (one for clockwise and one for counter clockwise rotation). In traditional games, the unsymetrical vertical orientation i-, z-, and s-pieces will fill the same columns for each clockwise and counter clockwise rotation. Newer releases fix this by allowing two possible column orientations-- one for counter clockwise and one for clockwise rotations. Double rotation, only seen in progressive clones such as Quadra, rotates the piece twice.
Piece preview allows a look at the next spawn. This feature has been implemented since the earliest games, though in those early games, having the preview turned on made the score increase more slowly.
Newest feature additions
Newer versions of Tetris add different scoring goals not present in traditional Tetris. As achieving these goals while not topping out becomes more difficult, these games usually add a few features to help the player.
The New Tetris and The Next Tetris were the first official Tetris games to feature multiple piece previews, showing 3 in advance. Tetris Worlds for PCs and game consoles added 5 more, while the GBA version retained the 3 piece preview of TNT.
Piece shadow is a feature that shows an obscuration in the shape of the current piece over where that piece would drop. The feature disposes with the old problem of misdrops and is relatively new.
Hold piece is an optional ability to reserve a piece for later use, allowing a player to either avoid undesirable pieces or save desirable ones, usually the I piece or a piece needed to complete another goal. Some clones featured it as a powerup that the player could earn and use once. A hold piece available to the player at all times was first featured in The New Tetris. Games that have hold piece generally activate it when the player presses both rotate buttons simultaneously or when the player presses a dedicated button, depending on the game. When hold piece is activated, it causes the falling piece to move to the top and trade places with the hold piece. However, the feature cannot be activated twice in a row; a piece released from the hold must be dropped into the well.
Tetris variants
A number of Tetris variants exist. Some feature alternate rules and pieces, and others have completely different gameplay. A large number of ports exist for different platforms. The most popular online client for Tetris is Tetris Worlds Live.
See article: Tetris variants
Is it possible to play forever?
Normally, players lose for the following reasons:
- they can no longer keep up with the increasing speed, or
- a specific implementation of the game with not very responsive control fails to keep up with itself when the pieces' downward velocity exceeds the maximum lateral velocity the player can apply to a tetromino. In other words, the possibilities for tetrominoes movement are limited to the shape of a cone in the game arena on faster levels. Some players may consider this situation a design flaw; however, it may be reasoned that this is an inherent challenge for the game. Altering this aspect, such as by assigning numerical placements, would change the dynamics of the game approach.
But what if speed was not a problem? Would it be possible to play forever? First encountered in a thesis by John Brzustowski in 1988 and more recently investigated in published articles by Walter Kosters, a player is inevitably doomed to lose.
The reason has to do with the S and Z tetrominoes. If a player receives a large sequence of S tetrominoes, naïve gravity eventually forces the player to leave a hole in a corner.
Suppose that player then receives a large sequence of Z tetrominoes. Eventually, that player will be forced to leave a hole in the opposite corner without clearing the previous hole. Back and forth, the holes will necessarily stack to the top. Since the pieces are distributed randomly, this sequence will eventually occur. If played long enough, and the random number generator is theoretically perfect, any player will lose the game. A detailed discussion of this scenerio can be found at http://www2.math.uic.edu/~burgiel/Tetris/, along with an implementation written in Java that has been modified to deal only S and Z tetrominoes.
Practically, this does not occur because the pseudorandom number generator in most implementations, which is usually a linear congruential generator, does not deal such a sequence.
Even on an implementation with a theoretically perfect random number generator (for example, based on hashing Brownian motion), a good player may survive over 150 consecutive S and Z tetrominoes. The probability at any given time of the next 150 tetrominoes being only S and Z is one in (7/2)150 (approximately one in 4 × 1081). This number has the same order of magnitude as the number of atoms in the known universe.[5]
Several of the subproblems of Tetris have been shown to be NP-complete on a playing field of size n.
Music
The theme tune used in the Game Boy and NES editions of Tetris (Music A) has become very widely known. It is a Russian folk tune called "Korobeyniki" or "Korobeiniki."
Odd Facts
- Until the Sega Saturn, Tetris never (legally) appeared on a Sega system. This led Sega to further expand the Columns series.
- Tetris JR was hinted at being the last Nintendo Game & Watch game but Nintendo canceled it, fearing that it would kill off Game Boy sales. Years later a Tetris JR would appear as a keychain game.
- Tetris was also referenced prominently in the video-game oriented cartoon Captain N: The Game Master.
External links
- The Father of Tetris
- Tetris Concept, with various information relating to Tetris
- The Killer List of Video Games entry on Atari's Tetris
- Tetris is Hard, Even to Approximate
- Tetris Company home page
- Copyright Registration for Computer Programs (PDF file)
- Information on game copyrighting from the Library of Congress
- Tetris Dreams, Scientific American summarizes a study of the phenomenon of "Tetris Dreams"
- Tetris: a history
- h2g2 article on Tetris