# Difference between revisions of "Tactical rotation"

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The New Tetris uses smooth falling animation for tetrominoes. The way this implementation mixes the falling animation with collision detection means that when a tetromino must be moved under an overhang to reach a ledge, by the time it has moved left one space with no support it has dropped more than zero spaces. In some cases it can therefore not reach a ledge.

Nothing can be done in the case of the O piece:

There is no problem getting the O piece to here

But if the ledge is further under the overhang we have a problem

The piece can not move left until this point

It cannot move left two spaces before it has dropped more than zero spaces

There are, however, ways of getting a piece other than O further under the overhang by making use of "tactical rotation": rotating the piece in the right direction at the right time.

## Examples

### L/J shuffle

This is useful for completing spiral L monosquares on the left and spiral J monosquares on the right (in which case the move is reversed).

Once the L is clear of the overhang it needs to slide two positions left to lock in place. This can't be done just by holding left

Firm drop the L to hang off the edge

Hold left, rotate clockwise then anticlockwise in quick succession

The L is moving through the corner piece. Keep holding left and soft drop, so it slides left as soon as it can.

Completed square

If the space above the block is already occupied in such a way that the L cannot be overhung as in the second figure, a trickier version can be performed:

Lower the L in this orientation

Start to hold left

Just as the L begins to move left, rotate anticlockwise

The L is moving through the corner piece: keep holding left and soft drop it into place

Finished square

### S/Z wiggle

This move is required for ZLLZ/SJJS and TTLZ/TTJS multisquares. The move is reversed for SJJS and TTJS multisquares.

The space marked with must be free

That surely won't fit...

Firm drop to here, then rotate clockwise then anticlockwise in quick succession

The Z piece is sliding through this position. Firm drop it.

Job done

### Reaching under overhangs

This works in a similar way to the trickier version of the L/J shuffle.

Hold left from here

As soon as the piece starts moving left, rotate anticlockwise (check if direction matters)

Now use the L/J shuffle

This can also be done with I pieces:

Just holding left from here won't get the I piece in place

Hold left from here

As long as the gravity isn't too strong at this point in the game, you'll get to here (or a space further down)

Rotate the I piece into place

### Building a T monosquare quickly

The quickest way to add the final piece of a T monosquare is to spin it into place:

Firm drop the backwards-oriented T piece

Rotate the piece twice quickly

Finished square

If there is no free space above:

With the T piece oriented backwards hold left and soft drop

It catches in the gap. Rotate the piece twice quickly

Finished square