- Code: Select all
+-------+-------+-------+
| . 9 . | . 1 . | 4 . . |
| 1 . 2 | 3 . 4 | . 5 . |
| . 5 . | . 7 . | . . 6 |
+-------+-------+-------+
| . 3 . | . 2 . | 9 . . |
| 6 . 8 | 5 . 9 | . 3 . |
| . 1 . | . 3 . | . . 7 |
+-------+-------+-------+
| . . 7 | . . 3 | . . . |
| . 2 . | . 5 . | . . . |
| 3 . . | 2 . . | . . . |
+-------+-------+-------+
.9..1.4..1.23.4.5..5..7...6.3..2.9..6.85.9.3..1..3...7..7..3....2..5....3..2.....
(source: Sudoku Architect)