ref: 526f63106b232665a8288ebf2d79c8ad659a2e37
dir: /sys/games/lib/sudoku/boards/easy-2005-02-11.su/
.6.....8. ..25..... .7..864.2 68...21.. ..73.58.. ..54...63 3.864..5. .....13.. .5.....9. 164239587 832574916 579186432 683792145 417365829 925418763 398647251 246951378 751823694