9	7	6			8
				6		3	1
		5			7	9	8
	9	8		2	6			4
	6						2
1			7	8		6	5
	1	2	3			8
	2	9		1
			9			4	7	6

Difficulty: Very easy (0)

		9	7			5		3
2				9	7
		6	8	5		7	9
4	9	8	2	6		3
	8						3
		1		2	3	6	4	7
	3	4		7	6	9
			6	3				4
7		3			2	8

Difficulty: Very easy (0)

1	9					6	5
		1	5			4
5	1			4	2
3		4					7
8	4		2		7		6	3
	6					8		1
			9	2			3	8
		2			6	7
	7	8					4	6

Difficulty: Very easy (0)

1			2		6		3
				6	4	2	9	7
	7			3				1
	8		1			9	6
		7				5
	1	2			8		5
6				9			2
4	5	6	7	8
	6		3		5			4

Difficulty: Very hard (0)