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Chapter 41: Palisade

You're given a grid of squares, some of which contain numbers. Your goal is to subdivide the grid into contiguous regions, all of the same (given) size, such that each square containing a number is adjacent to exactly that many edges (including those between the inside and the outside of the grid).

Credit for this puzzle goes to Nikoli, who call it ‘Five Cells’. [22].

Palisade was contributed to this collection by Jonas Kölker.

[22] https://www.nikoli.co.jp/en/puzzles/five_cells/

41.1 Palisade controls

Left-click to place an edge. Right-click to indicate ‘no edge’.

Alternatively, the arrow keys will move a keyboard cursor. Depending on the ‘Cursor mode’ preference (see section 41.3), the cursor will either navigate among the grid squares, or along their borders. In ‘Full-grid’ mode, hold Control while pressing an arrow key to place an edge, and press Shift-arrowkey to switch off an edge. In ‘Half-grid’ mode, press Enter to place an edge, and Space to switch off an edge. In either mode, you can repeat an action to perform its inverse.

(All the actions described in section 2.1 are also available.)

41.2 Palisade parameters

These parameters are available from the ‘Custom...’ option on the ‘Type’ menu.

Width, Height
Size of grid in squares.
Region size
The size of the regions into which the grid must be subdivided.

41.3 Palisade user preferences

On platforms that support user preferences, the ‘Preferences’ option on the ‘Game’ menu will let you configure the behavior of the cursor keys to either navigate among full grid squares, or along the borders of the grid squares.


[Simon Tatham's Portable Puzzle Collection, version 20240911.cd97968]