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

Difficulty: Very hard (0)

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

Difficulty: Super easy (0)

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

Difficulty: Very easy (0)

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

Difficulty: Very easy (0)