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, they have to depend on other tetrominoes to keep themself from topping out or to keep their field stable.
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.
If there is already an indent, fill up the cells to create the wall.
Funnels don't have to be limited to long and empty single columns.
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.