Celebrating 25 years of ‘Tetris Effect’ – One of the world’s most popular game

About Tetris

Tetris is a puzzle video game originally designed and programmed by Alexey Pajitnov on June 6, 1984. He derived its name from the Greek numerical prefix “tetra- (all of the game’s pieces, known as Tetrominoes, contain four segments) and tennis, Pajitnov’s favorite sport.

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, portable media players, PDAs and even as an Easter egg on non-media products like oscilloscopes. It has even been played on the sides of various buildings, with the record holder for the world’s largest fully functional game of Tetris being an effort by Dutch students in 1995 that lit up all 15 floors of the Electrical Engineering department at Delft University of Technology.

While versions of Tetris were sold for a range of 1980s home computer platforms, it was the hugely successful handheld version for the Game Boy launched in 1989 that established the reputation of the game as one of the most popular ever. Electronic Gaming Monthly’s 100th issue had Tetris in first place as “Greatest Game of All Time”. In 2007, Tetris came in second place in IGN’s “100 Greatest Video Games of All Time” selling more than 70 million copies.

Gameplay

A random sequence of tetrominoes (sometimes called “tetrads” in older versions)—shapes composed of four square blocks each—fall down the playing field (a rectangular vertical shaft, called the “well” or “matrix”). The object of the game is to manipulate these tetrominoes, by moving each one sideways and rotating it by 90 degree units, with the aim of creating a horizontal line of blocks without gaps. When such a line is created, it disappears, and any block above the deleted line will 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 and no new tetrominoes are able to enter.

There are many other formats/versions of the game available today. Some of which are Tetris Acorn Drop, Tetris Sprint, Tetris Battle, Tetris Marathon, Tetirs Ultra, Tetris 1989, Tetris Survival, Tetris N-Blox, etc.

Color of tetriminoes

Pajitnov’s original version for the Elektronika 60 computer used green brackets to represent blocks.Versions of Tetris on the original Game Boy and on most dedicated handheld games use monochrome or grayscale graphics, but most popular versions use a separate color for each distinct shape. Prior to The Tetris Company’s standardization in the early 2000s, those colors varied widely from implementation to implementation.

Scoring formula

The scoring formula for the majority of Tetris products is built on the idea that more difficult line clears should be awarded more points. For example, a single line clear in Tetris Zone is worth 100 points, while a back-to-back Tetris is worth 1,200.

Nearly all Tetris games allow the player to press a button to increase the speed of the current piece’s descent, rather than waiting for it to fall. If the player can stop the increased speed before the piece reaches the floor by letting go of the button, this is a “soft drop”; otherwise, it is a “hard drop” (some games allow only soft drop or only hard drop; others have separate buttons). Many games award a number of points based on the height that the piece fell before locking.

End of play

Players can lose a typical game of Tetris when they can no longer keep up with the increasing speed, and the tetrominoes stack up to the top of the playing field.

Ever thought if it were possible to play to play the game forever?

This question was first encountered in a thesis by John Brzustowski in 1988 and has been more recently investigated in published articles by Walter Kosters. The conclusion reached was that 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, the naïve gravity used by the standard game 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. If the pieces are distributed randomly, this sequence will eventually occur. Thus, if a game with an ideal, uniform, uncorrelated random number generator is played long enough, any player will top out.

Practically, this does not occur in most of Tetris variants. Some variants allow the player to choose to play with only S and Z tetrominoes, and a good player may survive well over 150 consecutive tetrominoes this way. On an implementation with an ideal uniform randomizer, the probability at any given time of the next 150 tetrominoes being only S and Z is one in (2/7)^150 (approximately 2×10^-82). Most implementations use a pseudorandom number generator to generate the sequence of tetrominoes, and such an S–Z sequence is almost certainly not contained in the sequence produced by the 32-bit linear congruential generator in many implementations (which has roughly 4.2 × 10^9 states). In fact, newer Tetris brand games from 2001 and later tend to follow a new guideline such that the randomizer generates all seven tetrominoes in a permutation at one time, guaranteeing an even distribution over the short term,[citation needed] and this randomizer allows the player to continue a game indefinitely in theory, often clearing all blocks from the playfield.[citation needed] On the other hand, the “evil” algorithm in Bastet often starts a game with a series of more than seven Z pieces.

Recent versions of Tetris such as Tetris Worlds allow the player to continuously rotate a block once it hits the bottom of the playfield, without it locking into place (see Easy spin dispute, above). This permits a player to play for an infinite amount of time, though not necessarily to land an infinite number of blocks.

About Tetris

Tetris is a puzzle video game originally designed and programmed by Alexey Pajitnov on June 6, 1984. He derived its name from the Greek numerical prefix “tetra- (all of the game’s pieces, known as Tetrominoes, contain four segments) and tennis, Pajitnov’s favorite sport.

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, portable media players, PDAs and even as an Easter egg on non-media products like oscilloscopes. It has even been played on the sides of various buildings, with the record holder for the world’s largest fully functional game of Tetris being an effort by Dutch students in 1995 that lit up all 15 floors of the Electrical Engineering department at Delft University of Technology.

While versions of Tetris were sold for a range of 1980s home computer platforms, it was the hugely successful handheld version for the Game Boy launched in 1989 that established the reputation of the game as one of the most popular ever. Electronic Gaming Monthly’s 100th issue had Tetris in first place as “Greatest Game of All Time”. In 2007, Tetris came in second place in IGN’s “100 Greatest Video Games of All Time” selling more than 70 million copies.

Gameplay

A random sequence of tetrominoes (sometimes called “tetrads” in older versions)—shapes composed of four square blocks each—fall down the playing field (a rectangular vertical shaft, called the “well” or “matrix”). The object of the game is to manipulate these tetrominoes, by moving each one sideways and rotating it by 90 degree units, with the aim of creating a horizontal line of blocks without gaps. When such a line is created, it disappears, and any block above the deleted line will 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 and no new tetrominoes are able to enter.

There are many other formats/versions of the game available today. Some of which are Tetris Acorn Drop, Tetris Sprint, Tetris Battle, Tetris Marathon, Tetirs Ultra, Tetris 1989, Tetris Survival, Tetris N-Blox, etc.

The first Tetris game

Color of tetriminoes

Pajitnov’s original version for the Elektronika 60 computer used green brackets to represent blocks.Versions of Tetris on the original Game Boy and on most dedicated handheld games use monochrome or grayscale graphics, but most popular versions use a separate color for each distinct shape. Prior to The Tetris Company’s standardization in the early 200s, those colors varied widely from implementation to implementation.

Tetrominoes

Scoring formula

The scoring formula for the majority of Tetris products is built on the idea that more difficult line clears should be awarded more points. For example, a single line clear in Tetris Zone is worth 100 points, while a back-to-back Tetris is worth 1,200.

Nearly all Tetris games allow the player to press a button to increase the speed of the current piece’s descent, rather than waiting for it to fall. If the player can stop the increased speed before the piece reaches the floor by letting go of the button, this is a “soft drop”; otherwise, it is a “hard drop” (some games allow only soft drop or only hard drop; others have separate buttons). Many games award a number of points based on the height that the piece fell before locking.

End of play

Players can lose a typical game of Tetris when they can no longer keep up with the increasing speed, and the tetrominoes stack up to the top of the playing field.

Ever thought if it were possible to play to play the game forever?

This question was first encountered in a thesis by John Brzustowski in 1988 and has been more recently investigated in published articles by Walter Kosters. The conclusion reached was that 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, the naïve gravity used by the standard game 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. If the pieces are distributed randomly, this sequence will eventually occur. Thus, if a game with an ideal, uniform, uncorrelated random number generator is played long enough, any player will top out.

Practically, this does not occur in most of Tetris variants. Some variants allow the player to choose to play with only S and Z tetrominoes, and a good player may survive well over 150 consecutive tetrominoes this way. On an implementation with an ideal uniform randomizer, the probability at any given time of the next 150 tetrominoes being only S and Z is one in (2/7)^150 (approximately 2×10^-82). Most implementations use a pseudorandom number generator to generate the sequence of tetrominoes, and such an S–Z sequence is almost certainly not contained in the sequence produced by the 32-bit linear congruential generator in many implementations (which has roughly 4200000000 states). In fact, newer Tetris brand games from 2001 and later tend to follow a new guideline such that the randomizer generates all seven tetrominoes in a permutation at one time, guaranteeing an even distribution over the short term, and this randomizer allows the player to continue a game indefinitely in theory, often clearing all blocks from the playfield. On the other hand, the “evil” algorithm in Bastet often starts a game with a series of more than seven Z pieces.

Recent versions of Tetris such as Tetris Worlds allow the player to continuously rotate a block once it hits the bottom of the playfield, without it locking into place (see Easy spin dispute, above). This permits a player to play for an infinite amount of time, though not necessarily to land an infinite number of blocks.