PlaySudoku.us
Hard · Puzzle #23
4
7
1
8
3
5
3
1
6
7
5
8
2
7
4
5
9
1
7
2
8
3
2
4
1
6
3
"A theory that is not refutable by any conceivable event is non-scientific." — Karl Popper
"A theory that is not refutable by any conceivable event is non-scientific." — Karl Popper
"In the middle of every difficulty lies opportunity." — Albert Einstein
"In the middle of every difficulty lies opportunity." — Albert Einstein