Btw, esot tāds nxn grid, šodien tehnikas listē par to fleims:
An nxn grid is an undirected graph consisting of n rows and n columns
of vertices, as shown in Figure 27.12. We denote the vertex in the ith
row and the jth colun by (i,j). All vertices in a grid have exactly four
neighbors, except for the boundary vertices, which are the points (i,j)
for which i=1, i=n, j=1, or j=n.

Figūriņa šāda, tikai lielāka:

O---O---O---O
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O---O---O---O
| | | |
O---O---O---O
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O---O---O---O