Meowdoku! Four-Cell L-Shape Elimination Guide

To solve a four-cell L-shaped color region in Meowdoku! without guessing, evaluate the squares outside the shape that are blocked by all four possible cat placements. Each color region must contain exactly one cat, and cats cannot touch horizontally, vertically, or diagonally. Because the cat must occupy one of the four tiles in the region, any external square that borders or aligns with all four candidates can never legally hold a cat and can be marked with an X immediately.

Why the Inner Corner Is Always Eliminated

The inner crook of a four-cell L-shape is universally blocked by adjacency rules alone, regardless of the rest of the board.

When an L-shape occupies a 3x2 area with a three-cell vertical stem and a one-cell foot, the empty space inside the bend touches every tile in the region:

Because the mandatory cat must land on one of these four tiles, the inner corner square at (Row 2, Col 2) is threatened in every outcome. Mark this inner pocket with an X right away without checking other rows or columns.

[ Cat 1 ] [   .   ]
[ Cat 2 ] [  X !  ]  <-- Inner corner touches all 4 candidates
[ Cat 3 ] [ Cat 4 ]

How to Test Placements for Shared Eliminations

Beyond the guaranteed inner corner, testing all four candidate positions reveals whether a second external tile is also eliminated across every scenario.

1. Verify the region footprint: Count the squares to ensure the colored region is strictly four cells arranged as a three-cell line with one perpendicular extension.
2. Mark the inner corner: Place an X on the concave cell sitting inside the bend.
3. Simulate Candidate 1 (Stem Tip): Note the row, column, and all eight surrounding squares it eliminates.
4. Simulate Candidate 2 (Stem Center): Check the row, column, and adjacent squares it eliminates, watching for overlap with Candidate 1.
5. Simulate Candidate 3 (Stem Base): Note the eliminations caused by the corner joint of the L-shape.
6. Simulate Candidate 4 (The Foot): Check the orthogonal lines and diagonal touch points extending from the offset square.
7. Mark overlapping danger zones: If any external square is rendered invalid under Candidate 1, Candidate 2, Candidate 3, and Candidate 4, place an X on that square.

Next Steps After Marking Shared Xs

Once you place the guaranteed X marks around the L-shape, shift your focus to the neighboring color regions that share those squares:

• Check shortened neighbor regions: If an eliminated square belonged to an adjacent two- or three-cell territory, check whether that territory now has only one valid tile left.
• Resolve singletons: If a neighbor region is reduced to one available square, place the cat there immediately, then mark an X across its entire row, column, and surrounding eight tiles.
• Avoid extended L-shapes: Do not apply the immediate inner-corner rule to shapes with stems longer than three cells without testing them manually, as an extended stem breaks the universal diagonal contact with a single corner tile.