ref: ac3147a9c58f339f9b978ab087464912c16bc8f8
dir: /sys/games/lib/sudoku/boards/medium-2005-02-01.su/
...2...3. ..9.8.264 1...36.9. 4.3...... .8..2..1. ......8.6 .4.75...3 375.4.1.. .2...8... 864279531 739185264 152436798 413867952 586924317 297513846 948751623 375642189 621398475