ref: 457ba087b13a881b013940f6e54c09566ec10ed1
dir: /sys/games/lib/sudoku/boards/medium-2005-05-26.su/
.92..854. .8.156... 1....4... 75....... ..4...9.. .......52 ...3....9 ...562.3. .279..46. 692738541 483156297 175294683 759623814 234815976 816479352 568347129 941562738 327981465