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*>Tepples
(→‎Delay: more vague to accommodate more games)
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A ''single'' is the act of clearing one line at a time:
A ''single'' is the act of clearing one line at a time:
{|
{|
|{{pfstart}}
|<playfield>
{{pfrow | | | | | | | | | | }}
..........
{{pfrow |g| |g| |g| | | | |t}}
G.G.G....T
{{pfrow |g|g|g|g|g|g|g|g|t|t}}
GGGGGGGGTT
{{pfrow |g|g|g|g|g|g| |g|g|t}}
GGGGGG.GGT
{{pfend}}
</playfield>
|{{pfstart}}
|<playfield>
{{pfrow | | | | | | | | | | }}
..........
{{pfrow |g| |g| |g| | | | |t}}
G.G.G....T
{{pfrow |-|-|-|-|-|-|-|-|-|-}}
----------
{{pfrow |g|g|g|g|g|g| |g|g|t}}
GGGGGG.GGT
{{pfend}}
</playfield>
|{{pfstart}}
|<playfield>
{{pfrow | | | | | | | | | | }}
..........
{{pfrow | | | | | | | | | | }}
..........
{{pfrow |g| |g| |g| | | | |t}}
G.G.G....T
{{pfrow |g|g|g|g|g|g| |g|g|t}}
GGGGGG.GGT
{{pfend}}
</playfield>
|}
|}
===Double===
===Double===
A ''double'' is when two lines are cleared at once:
A ''double'' is when two lines are cleared at once:
{|
{|
|{{pfstart}}
|<playfield>
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | | | |g}}
.........G
{{pfrow|g|g| |g| |z| |g|g|g}}
GG.G.Z.GGG
{{pfrow|g|g|g|g|z|z|g|g|g|g}}
GGGGZZGGGG
{{pfrow|g|g|g|g|z|g|g|g|g|g}}
GGGGZGGGGG
{{pfend}}
</playfield>
|{{pfstart}}
|<playfield>
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | | | |g}}
.........G
{{pfrow|g|g| |g| |z| |g|g|g}}
GG.G.Z.GGG
{{pfrow|-|-|-|-|-|-|-|-|-|-}}
----------
{{pfrow|-|-|-|-|-|-|-|-|-|-}}
----------
{{pfend}}
</playfield>
|{{pfstart}}
|<playfield>
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | | | |g}}
.........G
{{pfrow|g|g| |g| |z| |g|g|g}}
GG.G.Z.GGG
{{pfend}}
</playfield>
|}
|}
===Triple===
===Triple===
A ''triple'' is three lines cleared simultaneously. Most games allow only I, L, and J tetrominoes to complete a triple, but newer games with [[SRS]] allow S, Z, and T tetrominoes to [[twist]] into seemingly impossible positions.
A ''triple'' is three lines cleared simultaneously. Most games allow only I, L, and J tetrominoes to complete a triple, but newer games with [[SRS]] allow S, Z, and T tetrominoes to [[twist]] into seemingly impossible positions.
{|
{|
|{{pfstart}}
|<playfield>
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | |g| | }}
.......G..
{{pfrow|g|g| | |g|g|g| |g|g}}
GG..GGG.GG
{{pfrow|g|g|l|l|g|g|g|g|g|g}}
GGLLGGGGGG
{{pfrow|g|g|g|l|g|g|g|g|g|g}}
GGGLGGGGGG
{{pfrow|g|g|g|l|g|g|g|g|g|g}}
GGGLGGGGGG
{{pfend}}
</playfield>
|{{pfstart}}
|<playfield>
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | |g| | }}
.......G..
{{pfrow|g|g| | |g|g|g| |g|g}}
GG..GGG.GG
{{pfrow|-|-|-|-|-|-|-|-|-|-}}
----------
{{pfrow|-|-|-|-|-|-|-|-|-|-}}
----------
{{pfrow|-|-|-|-|-|-|-|-|-|-}}
----------
{{pfend}}
</playfield>
|{{pfstart}}
|<playfield>
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | |g| | }}
.......G..
{{pfrow|g|g| | |g|g|g| |g|g}}
GG..GGG.GG
{{pfend}}
</playfield>
|}
|}
===Tetris===
===Tetris===
A ''tetris'' is four lines cleared simultaneously. In most games, this can only be done with an "I" tetromino.
A ''tetris'' is four lines cleared simultaneously. In most games, this can only be done with an "I" tetromino.
{|
{|
|{{pfstart}}
|<playfield>
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | |g|g|g|g|g|g| |g}}
..GGGGGG.G
{{pfrow| | |g|g|g|g|g|g| |g}}
..GGGGGG.G
{{pfrow|g| |g|g|g|g|g|g| |g}}
G.GGGGGG.G
{{pfrow|g|i|g|g|g|g|g|g|g|g}}
GIGGGGGGGG
{{pfrow|g|i|g|g|g|g|g|g|g|g}}
GIGGGGGGGG
{{pfrow|g|i|g|g|g|g|g|g|g|g}}
GIGGGGGGGG
{{pfrow|g|i|g|g|g|g|g|g|g|g}}
GIGGGGGGGG
{{pfrow|g|g|g|g|g|g|g|g| |g}}
GGGGGGGG.G
{{pfend}}
</playfield>
|{{pfstart}}
|<playfield>
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | |g|g|g|g|g|g| |g}}
..GGGGGG.G
{{pfrow| | |g|g|g|g|g|g| |g}}
..GGGGGG.G
{{pfrow|g| |g|g|g|g|g|g| |g}}
G.GGGGGG.G
{{pfrow|-|-|-|-|-|-|-|-|-|-}}
----------
{{pfrow|-|-|-|-|-|-|-|-|-|-}}
----------
{{pfrow|-|-|-|-|-|-|-|-|-|-}}
----------
{{pfrow|-|-|-|-|-|-|-|-|-|-}}
----------
{{pfrow|g|g|g|g|g|g|g|g| |g}}
GGGGGGGG.G
{{pfend}}
</playfield>
|{{pfstart}}
|<playfield>
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | |g|g|g|g|g|g| |g}}
..GGGGGG.G
{{pfrow| | |g|g|g|g|g|g| |g}}
..GGGGGG.G
{{pfrow|g| |g|g|g|g|g|g| |g}}
G.GGGGGG.G
{{pfrow|g|g|g|g|g|g|g|g| |g}}
GGGGGGGG.G
{{pfend}}
</playfield>
|}
|}
===<span id="Hurdle">Hurdle / Split</span>===
 
===Larger line clears===
{{see also|Clearing over four lines}}
 
In most games a Tetris is the largest possible line clear. However, for games which include [[pentomino]]es such as ''[[Magical Tetris Challenge]]'' and ''[[Puyo Puyo Tetris]]'' (in Party mode) it is possible to clear five lines. ''Magical Tetris Challenge'' refers to this as a Pentris, while ''Puyo Puyo Tetris'' refers to this as a Tetris Plus.
 
{|
|<playfield>
..........
......G...
.GGG.GGG..
GGGGGGGGG.
GGGGGGGGGI
GGGGGGGGGI
GGGGGGGGGI
GGGGGGGGGI
GGGGGGGGGI
</playfield>
|<playfield>
..........
......G...
.GGG.GGG..
GGGGGGGGG.
----------
----------
----------
----------
----------
</playfield>
|<playfield>
..........
..........
..........
..........
..........
..........
......G...
.GGG.GGG..
GGGGGGGGG.
</playfield>
|}
 
===<span id="Hurdle">Hurdle or Split</span>===
In ''Tetris DS'' mission mode, the act of clearing two or three lines separated by one or more rows with gaps is called a ''hurdle''. In the 1998 Sega Tetris, this move was called a split and it launched a special attack in VS mode. Any tetromino that can complete a triple can complete a hurdle:
In ''Tetris DS'' mission mode, the act of clearing two or three lines separated by one or more rows with gaps is called a ''hurdle''. In the 1998 Sega Tetris, this move was called a split and it launched a special attack in VS mode. Any tetromino that can complete a triple can complete a hurdle:
{|
{|
|{{pfstart}}
|<playfield>
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | |g|g| }}
.......GG.
{{pfrow|g|g| | |g|g|g| |g|g}}
GG..GGG.GG
{{pfrow|g|g|l|l|g|g|g|g|g|g}}
GGLLGGGGGG
{{pfrow| |g|g|l|g|g|g|g|g|g}}
.GGLGGGGGG
{{pfrow|g|g|g|l|g|g|g|g|g|g}}
GGGLGGGGGG
{{pfend}}
</playfield>
|{{pfstart}}
|<playfield>
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | |g|g| }}
.......GG.
{{pfrow|g|g| | |g|g|g| |g|g}}
GG..GGG.GG
{{pfrow|-|-|-|-|-|-|-|-|-|-}}
----------
{{pfrow| |g|g|l|g|g|g|g|g|g}}
.GGLGGGGGG
{{pfrow|-|-|-|-|-|-|-|-|-|-}}
----------
{{pfend}}
</playfield>
|{{pfstart}}
|<playfield>
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | |g|g| }}
.......GG.
{{pfrow|g|g| | |g|g|g| |g|g}}
GG..GGG.GG
{{pfrow| |g|g|l|g|g|g|g|g|g}}
.GGLGGGGGG
{{pfend}}
</playfield>
|}
|}
===Back-to-Back===
===Back-to-Back===
''Back-to-Back'' clears are any combination of two or more "difficult" line clears without an "easy" line clear between them.
''Back-to-Back'' clears are any combination of two or more "difficult" line clears without an "easy" line clear between them.
The recent games ''[[Tetris Worlds]]'' and ''[[Tetris DS]]'' consider a 4-line clear ("tetris") or a [[Twist|T-spin]] line clear to be difficult. In certain Tetris game modes, you can earn extra [[points]] or deal an additional line of [[garbage]] by clearing ''Back-to-Back''.
The recent games ''[[Tetris Worlds]]'' and ''[[Tetris DS]]'' consider a 4-line clear ("tetris") or a [[Twist|T-spin]] line clear to be difficult. In certain Tetris game modes, you can earn extra [[points]] or deal an additional line of [[garbage]] by clearing ''Back-to-Back''.
All types of "difficult" clears share the same state variable.
All types of "difficult" clears share the same state variable.
For example, a player can clear a line with a T-Spin Single using the T tetromino, then clear four lines with an I tetromino, still earning him a ''Back-to-Back'' tetris.
For example, a player can clear a line with a T-Spin Single using the T tetromino, then clear four lines with an I tetromino, still earning a ''Back-to-Back'' tetris.
===Combo===
===Combo===
A ''combo'' refers to making a line clear with one piece and sequentially making another clear with the next piece, and so on. Lacking in recent games, developers experimented with the concept in ''[[TGM]]'' and ''[[Magical Tetris Challenge]]'', both released in 1998.
A ''combo'' refers to making a line clear with one piece and sequentially making another clear with the next piece, and so on.
In some cases, drilling through garbage or [[skimming]] is likely to produce combos.
Not all games reward combos; those that do include the following:
* [[TGM series]]
* [[Magical Tetris Challenge]]
* [[Tetris Evolution]] (two of the achievements relate to back-to-back Tetris combos)
* [[Tetris Party]], and almost all subsequent official games
* [[DTET]]
* [[Cultris]]
* [[Tetramino (NES)]]
 
== Line clear gravity ==
== Line clear gravity ==
After a line clear, the blocks above the line move down.
After a line clear, the blocks above the line move down.
How they move down depends on the game.
How they move down depends on the game.
Some systems allow for "recursive gravity" that [[clearing over four lines|clears more than four lines with one piece]].
=== Naive ===
=== Naive ===
Most Tetris games use naive gravity. Here, the blocks above a cleared line move down by exactly the number of cleared lines below them. This can often leave floating blocks, unconnected to anything, after a line is cleared. Most tetromino based games use naive gravity.
Most tetromino based games use naive gravity. Here, the blocks above a cleared line move down by exactly the number of cleared lines below them. This can often leave floating blocks, unconnected to anything, after a line is cleared.  
{|
{|
|{{pfstart}}
|<playfield>
{{pfrow| | | | | | | | | | }}
..........
{{pfrow|j| | | | | |g|g| | }}
J.....GG..
{{pfrow|j|j|j|g|g|g|g|g|g|g}}
JJJGGGGGGG
{{pfrow| | |g|g|g|g|g|g|g|g}}
..GGGGGGGG
{{pfrow| |g|g|g|g|g|g|g|g|g}}
.GGGGGGGGG
{{pfrow| |g|g|g|g|g|g|g|g|g}}
.GGGGGGGGG
{{pfend}}
</playfield>
Drop J
Drop J
|{{pfstart}}
|<playfield>
{{pfrow| | | | | | | | | | }}
..........
{{pfrow|j| | | | | |g|g| | }}
J.....GG..
{{pfrow|-|-|-|-|-|-|-|-|-|-}}
----------
{{pfrow| | |g|g|g|g|g|g|g|g}}
..GGGGGGGG
{{pfrow| |g|g|g|g|g|g|g|g|g}}
.GGGGGGGGG
{{pfrow| |g|g|g|g|g|g|g|g|g}}
.GGGGGGGGG
{{pfend}}
</playfield>
Line clear
Line clear
|{{pfstart}}
|<playfield>
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | | | | }}
..........
{{pfrow|j| | | | | |g|g| | }}
J.....GG..
{{pfrow| | |g|g|g|g|g|g|g|g}}
..GGGGGGGG
{{pfrow| |g|g|g|g|g|g|g|g|g}}
.GGGGGGGGG
{{pfrow| |g|g|g|g|g|g|g|g|g}}
.GGGGGGGGG
{{pfend}}
</playfield>
Naive gravity
Naive gravity
|}
|}
=== Sticky ===
=== Sticky ===
The playfield is divided into connected segments using [http://en.wikipedia.org/wiki/Flood_fill flood fill]. Any blocks that are adjacent horizontally or vertically are marked as one segment, that is, they are treated as having "stuck" together. Each segment falls independently until it meets the floor or another block. Additional line clears may result.
The playfield is divided into connected segments using [http://en.wikipedia.org/wiki/Flood_fill flood fill]. Any blocks that are adjacent horizontally or vertically are marked as one segment, that is, they are treated as having "stuck" together. Each segment falls independently until it meets the floor or another block. Additional line clears may result.
{|
{|
|{{pfstart}}
|<playfield>
{{pfrow| | | | | | | | | | }}
..........
{{pfrow|j| | | | | |g|g| | }}
J.....GG..
{{pfrow|j|j|j|g|g|g|g|g|g|g}}
JJJGGGGGGG
{{pfrow| | |g|g|g|g| | |g|g}}
..GGGG..GG
{{pfrow| |g|g|g|g|g|g| |g|g}}
.GGGGGG.GG
{{pfrow| |g|g|g|g|g|g|g|g|g}}
.GGGGGGGGG
{{pfend}}
</playfield>
Drop J
Drop J
|{{pfstart}}
|<playfield>
{{pfrow| | | | | | | | | | }}
..........
{{pfrow|j| | | | | |g|g| | }}
J.....GG..
{{pfrow|-|-|-|-|-|-|-|-|-|-}}
----------
{{pfrow| | |g|g|g|g| | |g|g}}
..GGGG..GG
{{pfrow| |g|g|g|g|g|g| |g|g}}
.GGGGGG.GG
{{pfrow| |g|g|g|g|g|g|g|g|g}}
.GGGGGGGGG
{{pfend}}
</playfield>
Line clear
Line clear
|{{pfstart}}
|<playfield>
{{pfrow| | | | | | | | | | }}
..........
{{pfrow|z| | | | | |o|o| | }}
Z.....OO..
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | |g|g|g|g| | |g|g}}
..GGGG..GG
{{pfrow| |g|g|g|g|g|g| |g|g}}
.GGGGGG.GG
{{pfrow| |g|g|g|g|g|g|g|g|g}}
.GGGGGGGGG
{{pfend}}
</playfield>
Mark segments
Mark segments
|{{pfstart}}
|<playfield>
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | | | | }}
..........
{{pfrow|z| |g|g|g|g|o|o|g|g}}
Z.GGGGOOGG
{{pfrow| |g|g|g|g|g|g| |g|g}}
.GGGGGG.GG
{{pfrow| |g|g|g|g|g|g|g|g|g}}
.GGGGGGGGG
{{pfend}}
</playfield>
Segment [[image:OTet.png|O]] lands
Segment [[image:OTet.png|O]] lands
|{{pfstart}}
|<playfield>
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | |g|g|g|g|g|g|g|g}}
..GGGGGGGG
{{pfrow| |g|g|g|g|g|g| |g|g}}
.GGGGGG.GG
{{pfrow|z|g|g|g|g|g|g|g|g|g}}
ZGGGGGGGGG
{{pfend}}
</playfield>
Segment [[image:ZTet.png|Z]] lands
Segment [[image:ZTet.png|Z]] lands
|-
|-
|{{pfstart}}
|<playfield>
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | |g|g|g|g|g|g|g|g}}
..GGGGGGGG
{{pfrow| |g|g|g|g|g|g| |g|g}}
.GGGGGG.GG
{{pfrow|-|-|-|-|-|-|-|-|-|-}}
----------
{{pfend}}
</playfield>
Line clear #2
Line clear #2
|{{pfstart}}
|<playfield>
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | |l|l|l|l|l|l|l|l}}
..LLLLLLLL
{{pfrow| |l|l|l|l|l|l| |l|l}}
.LLLLLL.LL
{{pfrow| | | | | | | | | | }}
..........
{{pfend}}
</playfield>
Mark segments
Mark segments
|{{pfstart}}
|<playfield>
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | | | | | | | | | }}
..........
{{pfrow| | |l|l|l|l|l|l|l|l}}
..LLLLLLLL
{{pfrow| |l|l|l|l|l|l| |l|l}}
.LLLLLL.LL
{{pfend}}
</playfield>
Segment [[image:LTet.png|L]] lands
Segment [[image:LTet.png|L]] lands
|}
|}
Line 262: Line 318:
*''[[Super Scope 6]]'' Blastris A
*''[[Super Scope 6]]'' Blastris A
*''[[Tetris Blast]]'' and ''Bombliss''
*''[[Tetris Blast]]'' and ''Bombliss''
*''[[Super Tetris 3]]'' in ''Magicaliss'' mode
*''[[The Next Tetris]]'' (modifies rule such that only blocks of a single color can form a segment)
*''[[The Next Tetris]]'' (modifies rule such that only blocks of a single color can form a segment)
**Re-released as ''Tetris Worlds'' Sticky
**Re-released as ''Tetris Worlds'' Sticky
*''[[Lockjaw: The Overdose]]''
*''[[Lockjaw: The Overdose]]''
=== Cascade ===
=== Cascade ===
When each piece locks, its connections to other blocks in the piece are stored. After lines are cleared, each piece is marked as a separate segment, and then each segment falls independently until it meets the floor or another block, as in Sticky.
When each piece locks, its connections to other blocks in the piece are stored. After lines are cleared, each piece is marked as a separate segment, and then each segment falls independently until it meets the floor or another block, as in Sticky.
Line 274: Line 332:
Non-tetromino games:
Non-tetromino games:
*''[[Dr. Mario]]''
*''[[Dr. Mario]]''
*''Super Puzzle Fighter II''
== Delay ==
== Delay ==
Some games impose a line clear delay after each piece that completes one or more lines and/or a line gravity delay every time blocks move down by one row.
Some games impose a line clear delay after each piece that completes one or more lines and/or a line gravity delay every time blocks move down by one row.
Line 283: Line 343:
*[[Back to Back T-Spin Triple]]
*[[Back to Back T-Spin Triple]]


[[Category:Game Mechanics]]
[[Category:Interface]]
[[Category:Gameplay Components]]

Revision as of 10:35, 12 February 2019

The object of Tetris is to last as long as possible before the screen fills up with tetrominoes. To do this, you must assemble the tetrominoes to form one or more rows of blocks that span the entire playing field, called a line clear. When you do so, the row will disappear, causing the ones above it to settle.

Types of line clears

Single

A single is the act of clearing one line at a time:

..........
G.G.G....T
GGGGGGGGTT
GGGGGG.GGT
..........
G.G.G....T
----------
GGGGGG.GGT
..........
..........
G.G.G....T
GGGGGG.GGT

Double

A double is when two lines are cleared at once:

..........
.........G
GG.G.Z.GGG
GGGGZZGGGG
GGGGZGGGGG
..........
.........G
GG.G.Z.GGG
----------
----------
..........
..........
..........
.........G
GG.G.Z.GGG

Triple

A triple is three lines cleared simultaneously. Most games allow only I, L, and J tetrominoes to complete a triple, but newer games with SRS allow S, Z, and T tetrominoes to twist into seemingly impossible positions.

..........
.......G..
GG..GGG.GG
GGLLGGGGGG
GGGLGGGGGG
GGGLGGGGGG
..........
.......G..
GG..GGG.GG
----------
----------
----------
..........
..........
..........
..........
.......G..
GG..GGG.GG

Tetris

A tetris is four lines cleared simultaneously. In most games, this can only be done with an "I" tetromino.

..........
..GGGGGG.G
..GGGGGG.G
G.GGGGGG.G
GIGGGGGGGG
GIGGGGGGGG
GIGGGGGGGG
GIGGGGGGGG
GGGGGGGG.G
..........
..GGGGGG.G
..GGGGGG.G
G.GGGGGG.G
----------
----------
----------
----------
GGGGGGGG.G
..........
..........
..........
..........
..........
..GGGGGG.G
..GGGGGG.G
G.GGGGGG.G
GGGGGGGG.G

Larger line clears

See also: Clearing over four lines

In most games a Tetris is the largest possible line clear. However, for games which include pentominoes such as Magical Tetris Challenge and Puyo Puyo Tetris (in Party mode) it is possible to clear five lines. Magical Tetris Challenge refers to this as a Pentris, while Puyo Puyo Tetris refers to this as a Tetris Plus.

..........
......G...
.GGG.GGG..
GGGGGGGGG.
GGGGGGGGGI
GGGGGGGGGI
GGGGGGGGGI
GGGGGGGGGI
GGGGGGGGGI
..........
......G...
.GGG.GGG..
GGGGGGGGG.
----------
----------
----------
----------
----------
..........
..........
..........
..........
..........
..........
......G...
.GGG.GGG..
GGGGGGGGG.

Hurdle or Split

In Tetris DS mission mode, the act of clearing two or three lines separated by one or more rows with gaps is called a hurdle. In the 1998 Sega Tetris, this move was called a split and it launched a special attack in VS mode. Any tetromino that can complete a triple can complete a hurdle:

..........
.......GG.
GG..GGG.GG
GGLLGGGGGG
.GGLGGGGGG
GGGLGGGGGG
..........
.......GG.
GG..GGG.GG
----------
.GGLGGGGGG
----------
..........
..........
..........
.......GG.
GG..GGG.GG
.GGLGGGGGG

Back-to-Back

Back-to-Back clears are any combination of two or more "difficult" line clears without an "easy" line clear between them. The recent games Tetris Worlds and Tetris DS consider a 4-line clear ("tetris") or a T-spin line clear to be difficult. In certain Tetris game modes, you can earn extra points or deal an additional line of garbage by clearing Back-to-Back. All types of "difficult" clears share the same state variable. For example, a player can clear a line with a T-Spin Single using the T tetromino, then clear four lines with an I tetromino, still earning a Back-to-Back tetris.

Combo

A combo refers to making a line clear with one piece and sequentially making another clear with the next piece, and so on. In some cases, drilling through garbage or skimming is likely to produce combos. Not all games reward combos; those that do include the following:

Line clear gravity

After a line clear, the blocks above the line move down. How they move down depends on the game. Some systems allow for "recursive gravity" that clears more than four lines with one piece.

Naive

Most tetromino based games use naive gravity. Here, the blocks above a cleared line move down by exactly the number of cleared lines below them. This can often leave floating blocks, unconnected to anything, after a line is cleared.

..........
J.....GG..
JJJGGGGGGG
..GGGGGGGG
.GGGGGGGGG
.GGGGGGGGG

Drop J

..........
J.....GG..
----------
..GGGGGGGG
.GGGGGGGGG
.GGGGGGGGG

Line clear

..........
..........
J.....GG..
..GGGGGGGG
.GGGGGGGGG
.GGGGGGGGG

Naive gravity

Sticky

The playfield is divided into connected segments using flood fill. Any blocks that are adjacent horizontally or vertically are marked as one segment, that is, they are treated as having "stuck" together. Each segment falls independently until it meets the floor or another block. Additional line clears may result.

..........
J.....GG..
JJJGGGGGGG
..GGGG..GG
.GGGGGG.GG
.GGGGGGGGG

Drop J

..........
J.....GG..
----------
..GGGG..GG
.GGGGGG.GG
.GGGGGGGGG

Line clear

..........
Z.....OO..
..........
..GGGG..GG
.GGGGGG.GG
.GGGGGGGGG

Mark segments

..........
..........
..........
Z.GGGGOOGG
.GGGGGG.GG
.GGGGGGGGG

Segment O lands

..........
..........
..........
..GGGGGGGG
.GGGGGG.GG
ZGGGGGGGGG

Segment Z lands

..........
..........
..........
..GGGGGGGG
.GGGGGG.GG
----------

Line clear #2

..........
..........
..........
..LLLLLLLL
.LLLLLL.LL
..........

Mark segments

..........
..........
..........
..........
..LLLLLLLL
.LLLLLL.LL

Segment L lands

Games that use sticky gravity:

Cascade

When each piece locks, its connections to other blocks in the piece are stored. After lines are cleared, each piece is marked as a separate segment, and then each segment falls independently until it meets the floor or another block, as in Sticky. Games that use cascade gravity:

  • Tetris 2 (Tetris Flash)
  • Quadra
  • Tetris Worlds Cascade and Fusion
  • Tetris DS Touch

Non-tetromino games:

Delay

Some games impose a line clear delay after each piece that completes one or more lines and/or a line gravity delay every time blocks move down by one row. For example, Tetris The Grand Master and Tetris DS wait 400–700 ms. In games with a large line clear delay and scoring based on play time, it is to the player's advantage to make multiple lines at once (triple or tetris) so that less time is spent in line clear delay.

See Also