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Skimming

From TetrisWiki

Skimming is a clearing method by which a player can use to make a stack even. Skimming is done by placing a tetromino either at the edge or at the surface of a stack and cleaing a line as a result. The technique is favorable in multiplayer tetris because it can save a player from topping out, flatten the field, or allow a player to tetris.

Skimming is especially effective in games that use combo scoring. In other games, skimming forfeits "back-to-back" bonuses and is penalized with more line clear delay per line.

Minimize I tetromino dependence

When a player is starved of I tetrominoes, he has to depend on other tetrominoes to keep himself from topping out or to keep his field stable.

GGGGGGGG..
GGGGGGGG..
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGG..
GGGGGGGGLL
GGGGGGGGGL
GGGGGGGGGL
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGOO
GGGGGGGGOO
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGS.
GGGGGGGGSS
GGGGGGGGGS
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGG...
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGJJJ
GGGGGGGGGJ
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.

A T can be used to skim, either directly or by creating an overhang to a T-Spin Double.

GGGGGGG...
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGTTT
GGGGGGGGTG
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G

Funnel

A field may not be set up for skimming without covering the open column. Stack around the open column to create a funnel for skimming efficiently. A funnel may be created by filling up the necessary cells to create the indent.

..........
GGG-----..
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
...OOJ....
GGGOOJJJ..
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.

If there is already an indent, fill up the cells to create the wall.

..........
GG--..GGGG
GGGG.GGGGG
GGGG.GGGGG
GGGG.GGGGG
.ZZ.......
GGZZ..GGGG
GGGG.GGGGG
GGGG.GGGGG
GGGG.GGGGG

Inverted Funnel

Funnels don't have to be limited to long and empty single columns.

..........
GGGG..--GG
GGGG..--GG
GGGG..GGGG
GGGG.GGGGG
..........
GGGG..OOGG
GGGG..OOGG
GGGG..GGGG
GGGG.GGGGG
GGGG..GGGG
GGGG..GGGG
GGGG..GGGG
GGGG..GGGG
GGGG..GGGG
GGGG..GGGG
GGGG..GGGG
GGGGS.GGGG
GGGGSSGGGG
GGGG.SGGGG
..........
GGGG..GGGG
GGGG..GGGG
GGGGS.GGGG
GGGG.SGGGG

Line Clear

A line clear can be used to create a funnel. In this example, using an L to clear the far right column will not result in a funnel. If an I was to be used instead, a JZ funnel will be created.

..........
GGGGGGG...
GGGGGGGGG.
GGGGGGGGG.
GGGGGGG.GG
GGGGGGG.GG
.........I
GGGGGGG..I
GGGGGGGGGI
GGGGGGGGGI
GGGGGGG.GG
GGGGGGG.GG
..........
..........
.........I
GGGGGGG..I
GGGGGGG.GG
GGGGGGG.GG
GGGGGGGG..
GGGGGGGG..
GGGGGGGG..
GGGGGGGG..
GGGGGGGG..
GGGGGGGGLL
GGGGGGGG.L
GGGGGGGG.L
..........
GGGGGGGG..
GGGGGGGG.L
GGGGGGGG.L

Tetrominos can create different funnels depending on their orientation when used to clear a line.

GGGGGGG...
GGGGGGG...
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGJJJ
GGGGGGG..J
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G
GGGGGGG...
GGGGGGG..J
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G
GGGGGGG...
GGGGGGG...
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGJ..
GGGGGGGJJJ
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G
GGGGGGG...
GGGGGGGJ..
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG..
GGGGGGGG..
GGGGGGGG..
GGGGGGGG..
GGGGGGGG..
GGGGGGGGLL
GGGGGGGG.L
GGGGGGGG.L
..........
GGGGGGGG..
GGGGGGGG.L
GGGGGGGG.L
GGGGGGGG..
GGGGGGGG..
GGGGGGGG..
GGGGGGGG..
GGGGGGGG..
GGGGGGGGL.
GGGGGGGGL.
GGGGGGGGLL
..........
GGGGGGGG..
GGGGGGGGL.
GGGGGGGGL.

Different tetrominoes can create the same funnel depending on their orientation when used to clear a line.

GGGGGGG...
GGGGGGG...
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGJ..
GGGGGGGJJJ
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
..........
GGGGGGGJ..
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGG...
GGGGGGG...
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGLLL
GGGGGGGL..
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
..........
GGGGGGGL..
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGG..
GGGGGGGG..
GGGGGGGG..
GGGGGGGG..
GGGGGGGG..
GGGGGGGG.J
GGGGGGGG.J
GGGGGGGGJJ
GGGGGGGG..
GGGGGGGGLL
GGGGGGGG.L
GGGGGGGG.L
GGGGGGGG..
GGGGGGGG.T
GGGGGGGGTT
GGGGGGGG.T

Overhang

Funnels can be formed by rotating tetrominoes under overhangs.

GGGGGGGG..
GGGGGGGG..
GGGGGGG...
GGGGGGGG..
GGGGGGGGG.
GGGGGGGG..
GGGGGGGGT.
GGGGGGG.TT
GGGGGGGGT.
GGGGGGGGG.
GGGGGGGG..
GGGGGGGG..
GGGGGGGTTT
GGGGGGGGT.
GGGGGGGGG.
GGGGGGGG..
GGGGGGGGT.
GGGGGGGTT.
GGGGGGGGT.
GGGGGGGGG.
GGGGGGGG..
GGGGGGG...
GGGGGGGG..
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGT.
GGGGGGG.TT
GGGGGGGGT.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGG..
GGGGGGGTTT
GGGGGGGGT.
GGGGGGGGG.
GGGGGGGGG.
..........
GGGGGGGG..
GGGGGGGGT.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGG..
GGGGGGG...
GGGGGGGG..
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGG.Z
GGGGGGG.ZZ
GGGGGGGGZ.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGG..
GGGGGGGZZ.
GGGGGGGGZZ
GGGGGGGGG.
GGGGGGGGG.
..........
GGGGGGGG..
GGGGGGGZZ.
GGGGGGGGG.
GGGGGGGGG.

This only works in SRS.

GGGGGGGG..
GGGGGGGG..
GGGGGGG...
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGG..
GGGGGGGGS.
GGGGGGG.SS
GGGGGGGGGS
GGGGGGGGG.
GGGGGGGG..
GGGGGGGGSS
GGGGGGGSS.
GGGGGGGGG.
GGGGGGGGG.
..........
GGGGGGGG..
GGGGGGGSS.
GGGGGGGGG.
GGGGGGGGG.

This only works in ARS.

GGGGGGGG..
GGGGGGGG..
GGGGGGG...
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGI.
GGGGGGGGII
GGGGGGG.I.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGG..
GGGGGGGGI.
GGGGGGGIII
GGGGGGGGG.
GGGGGGGGG.
..........
GGGGGGGG..
GGGGGGGGI.
GGGGGGGGG.
GGGGGGGGG.

This works only in SRS with the exception of TGM3's Classic rotation system (an ARS variant), where the T is given a floor kick.

GGGGGGGG..
GGGGGGGG..
GGGGGGG...
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGG..
GGGGGGGG.T
GGGGGGG.TT
GGGGGGGGGT
GGGGGGGGG.
GGGGGGGG..
GGGGGGGGT.
GGGGGGGTTT
GGGGGGGGG.
GGGGGGGGG.
..........
GGGGGGGG..
GGGGGGGGT.
GGGGGGGGG.
GGGGGGGGG.

Twist

Twists may be used to create funnels.

GGGGGGGG..
GGGGGGG...
GGGGGGGG.G
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGT.
GGGGGGG.TT
GGGGGGGGTG
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGG..
GGGGGGGPPP
GGGGGGGGPG
GGGGGGGGG.
GGGGGGGGG.
..........
..........
GGGGGGGG..
GGGGGGGGG.
GGGGGGGGG.
GGGGGGG...
GGGGGG....
GGGGGGG.GG
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGT..
GGGGGG.TT.
GGGGGGGTGG
GGGGGGGGG.
GGGGGGGGG.
GGGGGGG...
GGGGGGTTT.
GGGGGGGTGG
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGP..
GGGGGGPP..
GGGGGGGPGG
GGGGGGGGG.
GGGGGGGGG.
..........
GGGGGGGT..
GGGGGGTT..
GGGGGGGGG.
GGGGGGGGG.

These only work in SRS.

GGGGGGGG..
GGGGGGGG..
GGGGGGG...
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGG.J
GGGGGGGG.J
GGGGGGG.JJ
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGG..
GGGGGGGG..
GGGGGGGJJJ
GGGGGGGGGJ
GGGGGGGGG.
..........
..........
GGGGGGGG..
GGGGGGGG..
GGGGGGGGG.
GGGGGGG...
GGGGGGG...
GGGGGGG.GG
GGGGGGGGG.
GGGGGGGGG.
GGGGGGG.T.
GGGGGGGTTT
GGGGGGG.GG
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGP..
GGGGGGGPP.
GGGGGGGPGG
GGGGGGGGG.
GGGGGGGGG.
..........
GGGGGGGT..
GGGGGGGTT.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGG...
GGGGGGG...
GGGGGGG...
GGGGGGGGG.
GGGGGGGGG.
GGGGGGG.T.
GGGGGGGTTT
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGG..P
GGGGGGG.PP
GGGGGGGGGP
GGGGGGGGG.
GGGGGGGGG.
..........
GGGGGGG..T
GGGGGGG.TT
GGGGGGGGG.
GGGGGGGGG.

Alternative Funnel

Funnels can be set up without utilizing the open column.

GGGGGGG...
GGGGGGG...
GGGGGGG...
GGGGGGGGG.
GGGGGGGGG.
GGGGGGG..Z
GGGGGGG.ZZ
GGGGGGG.Z.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGJJZ
GGGGGGGJZZ
GGGGGGGJZ.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGG...
GGGGGGG...
GGGGGGG...
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGG...
GGGGGGG.SS
GGGGGGGSS.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGLLL
GGGGGGGLSS
GGGGGGGSS.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGG....
GGGGGG....
GGGGGGG...
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G
GGGGGG....
GGGGGG..OO
GGGGGGG.OO
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G
GGGGGGS...
GGGGGGSSOO
GGGGGGGSOO
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G

Suspended Funnel

Funnels can be extended over a column.

GGGGGG....
GGGGGGG...
GGGGGGGGG.
GGGGGGGG..
GGGGGG....
GGGGGGGJJJ
GGGGGGGGGJ
GGGGGGGG..
GGGGGG....
GGGGGGG...
GGGGGGGGG.
GGGGGGGG..
GGGGGGZZ..
GGGGGGGZZ.
GGGGGGGGG.
GGGGGGGG..
GGGGGGZZLL
GGGGGGGZZL
GGGGGGGGGL
GGGGGGGG..
GGGGGGG...
GGGGGGG...
GGGGGGGG..
GGGGGGGG..
GGGGGGGS..
GGGGGGGSS.
GGGGGGGGS.
GGGGGGGG..
GGGGGGGSLL
GGGGGGGSSL
GGGGGGGGSL
GGGGGGGG..
GGGGGGG...
GGGGGGG...
GGGGGGGOO.
GGGGGGGOO.
GGGGGGGG..
GGGGGGG...
GGGGGGGJJJ
GGGGGGGOOJ
GGGGGGGOO.
GGGGGGGG..
..........
..........
GGGGGGGJJJ
GGGGGGGOOJ
GGGGGGGG..
GGGGGGG...
GGGGGGG...
GGGGGGGOO.
GGGGGGGOO.
GGGGGGGG..
GGGGGGG...
GGGGGGG.LL
GGGGGGGOOL
GGGGGGGOOL
GGGGGGGG..
..........
..........
GGGGGGGLLL
GGGGGGGLLL
GGGGGGGG..

Alternate

Funnels can be mirrored with various line clears that raise the wall on the opposite side.

GGGGGG....
GGGGGGG..G
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G
GGGGGGZZ..
GGGGGGGZZG
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G
..........
GGGGGGZZ..
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G
GGGGGGG...
GGGGGGGG..
GGGGGGGG..
GGGGGGGG.G
GGGGGGGG.G
GGGGGGG..T
GGGGGGGGTT
GGGGGGGG.T
GGGGGGGG.G
GGGGGGGG.G
..........
GGGGGGG..T
GGGGGGGG.T
GGGGGGGG.G
GGGGGGGG.G
GGGGGGG...
GGGGGGGG..
GGGGGGGG..
GGGGGGGG.G
GGGGGGGG.G
GGGGGGG..J
GGGGGGGG.J
GGGGGGGGJJ
GGGGGGGG.G
GGGGGGGG.G
..........
GGGGGGG..J
GGGGGGGG.J
GGGGGGGG.G
GGGGGGGG.G

The concept can be taken further. In this example, the S tetromino can convert the LS funnel into a JZ funnel. The process may be repeated until the wall on either side of the funnel becomes too short to skim any further.

GGGGGGG...
GGGGGGG...
GGGGGGG..G
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G
GGGGGGG...
GGGGGGGS..
GGGGGGGSSG
GGGGGGGGSG
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G
..........
..........
GGGGGGG...
GGGGGGGS..
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G
..........
..........
GGGGGGG..Z
GGGGGGGSZZ
GGGGGGGGZG
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G
..........
..........
..........
..........
GGGGGGG..Z
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G
..........
..........
..........
.......S..
GGGGGGGSSZ
GGGGGGGGSG
GGGGGGGG.G
GGGGGGGG.G
GGGGGGGG.G

Inverted funnels can be mirrored efficiently with a J/L or T tetromino.

GGGGGGGG..
GGGGGGGG..
GGGGGGGG..
GGGGGGGG..
GGGGGGGGG.
GGGGGGGG..
GGGGGGGG..
GGGGGGGGLL
GGGGGGGG.L
GGGGGGGGGL
..........
..........
GGGGGGGG..
GGGGGGGG..
GGGGGGGG.L
GGGGGGGG..
GGGGGGGG..
GGGGGGGG..
GGGGGGGG..
GGGGGGGGG.
GGGGGGGG..
GGGGGGGG..
GGGGGGGG.T
GGGGGGGGTT
GGGGGGGGGT
..........
..........
GGGGGGGG..
GGGGGGGG..
GGGGGGGG.T

Fill

When unable to tetris because of a funnel, fill it up. The main idea is to fill up more rows than the amount you clear. Technically, the I tetromino would be the best choice since it clears no rows, but it requires the player to have another I tetromino on hand. Therefore, the next best choices are the L, the J, and the T because they clear only one row for every 2 they complete. The S/Z tetromino clears two rows for every two rows it completes, which cancels out any effects.

GGGGGGGG..
GGGGGGGG..
GGGGGGGG..
GGGGGGGG..
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGG..
GGGGGGGGL.
GGGGGGGGL.
GGGGGGGGLL
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGG..
GGGGGGGGJJ
GGGGGGGGJ.
GGGGGGGGJ.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGG..
GGGGGGGGT.
GGGGGGGGTT
GGGGGGGGT.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.

Flatten

Step pyramid and castle structures may become an obstacle when stacking for a tetris. Only specific tetrominos can fit, which limits a player's placement options. Minor line clears can be performed to flatten the structures.

GGGGGG....
GGGGGG....
GGGGGGG...
GGGGGGGG..
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGG....
GGGGGG....
GGGGGGGZZ.
GGGGGGGGZZ
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGG....
GGGGGG....
GGGGGGGTTT
GGGGGGGGT.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGG....
GGGGGG....
GGGGGGG...
GGGGGGG.G.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGG....
GGGGGG....
GGGGGGGLLL
GGGGGGGLG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
..........
GGGGGG....
GGGGGG....
GGGGGGGLG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.

Order

When skimming consecutively, the order in which tetrominoes are used can make a difference. Tetromino properties have to be considered.

In this situation, clearing with an S first eliminates the funnel, disallowing any further skimming without covering the open column.

GGGGGGGG..
GGGGGGGG..
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGS.
GGGGGGGGSS
GGGGGGGGGS
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
..........
........LL
GGGGGGGGSL
GGGGGGGGGL
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.

Instead, if an L was to be used first, the funnel would still exist.

GGGGGGGG..
GGGGGGGG..
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGG..
GGGGGGGGLL
GGGGGGGGGL
GGGGGGGGGL
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
..........
..........
........S.
GGGGGGGGSS
GGGGGGGGGS
GGGGGGGGG.
GGGGGGGGG.

The same principle also applies to inverted funnels. In this example, clearing with a T first takes away the opportunity of skimming with an L.

GGGGGG..GG
GGGGGG..GG
GGGGGG..GG
GGGGGGG.GG
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGG..GG
GGGGGG.TGG
GGGGGGTTGG
GGGGGGGTGG
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
..........
..........
GGGGGG..GG
GGGGGG.TGG
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.

If the L was to be used first, the funnel would still be able to accomodate the T.

GGGGGG..GG
GGGGGG..GG
GGGGGG..GG
GGGGGGG.GG
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
GGGGGG..GG
GGGGGGLLGG
GGGGGG.LGG
GGGGGGGLGG
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.
..........
......T...
GGGGGGTTGG
GGGGGGTLGG
GGGGGGGGG.
GGGGGGGGG.
GGGGGGGGG.

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This page was last modified on 4 August 2009, at 20:43. - Disclaimers - About TetrisWiki