Plan 9 from Bell Labs’s /usr/web/sources/plan9/sys/games/lib/sudoku/boards/hard-2005-03-26.su
..8..457. ......... .1..726.3 .....8.1. .62.1.84. .8.5..... 5.169..3. ......... .498..7.. 238164579 796385124 415972683 957248316 362719845 184536297 521697438 873451962 649823751
