Tiling hex grid mapping (ASCII version)

Hex grids use the following mapping between (column,row) to nodes:

     ___     ___
    /0,0\___/2,0\___
    \___/1,0\___/3,0\
    /0,1\___/2,1\___/
    \___/1,1\___/3,1\
    /0,2\___/2,2\___/
    \___/1,2\___/3,2\
        \___/   \___/
    

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