LITS
Sample
Solution
Inaba
⇒
Rules
1.Color four consecutive squares (tetrominoes) in each of the areas
surrounded by bold lines.
2.Similarly shaped rotated or reversed tetrominoes cannot touch, except at
corners.
3.The colored squares must form a connected network.
4.Colored squares cannot form 2x2 or larger squares.
※quoted from Nikoli’ s website (http://www.nikoli.co.jp/en/puzzles/lits.html)
Challenge
Solution
1
First, color the squares which are to be colored to
form a tetromino in each of the area surrounded
by bold lines. The starred squares are to be
colored not to form 2x2 squares.
2
The X squares are to be blanks, not to form 2x2
3
If you color the black starred squares, you can’ t
squares with other tetrominoes.
color the white starred squares and consequently
can’ t form a tetromino in each of the areas
surrounded by bold lines.
Therefore, the black starred squares turn out to
be ‘X’ .
4
The lower right L-shaped tetromino has been
completed.
If you color the black starred square, the
tetromino in the area needs to be L-shaped
anyway. To avoid two Ls touching each other, the
black starred square is to be ‘X’ .
5
Unless the starred square is colored, the lower
right T-shaped tetromino will be isolated and
cannot form a connected network.
Therefore, the starred square is to be colored.
6
So far, you can decide to color (or not) these
squares.
If the starred square is colored, the tetromino in
the area will be T or L-shaped, and consequently
the same shaped tetrominoes touch each other
anyway.
Therefore, the starred square is to be ‘X’ .
7
Now let’ s look at the 3x3 area. No matter what
tetromino is placed there, it is impossible to touch
the four of the bold lines surrounding the area at
the same time. The tetromino in the upper right
3x3 is to come in contact with three tetrominoes
in the top, bottom, and left of it. It isn’ t to touch
the right side of the 3x3, and the starred squares
are to be blanks.
8
Well, the goal is just around the corner.
Unless the starred square is colored, the
tetromino in the 3x3 area below needs to touch
the four sides of the area. It’ s impossible, so the
starred square is to be colored.
Now color the squares to form a connected
network, avoiding the same shaped tetrominoes
touching each other.