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

Difficulty: Very easy (0)

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

Difficulty: Very easy (0)

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

Difficulty: Hard (0)

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

Difficulty: Very hard (0)