ref: ae61eb9381f6b0c70e1c52bf2c2b7f4cd0b5bb6f
dir: /sys/games/lib/sudoku/boards/vhard-2005-04-16.su/
.8....3.1 ..9.2..4. 7.......5 ..7.36.9. ......... .9.75.4.. 1.......2 .5..6.8.. 3.4....6. 486579321 539821647 721643985 217436598 645918273 893752416 168394752 952167834 374285169