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

Difficulty: Very easy (0)

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

Difficulty: Super easy (0)

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

Difficulty: Harder (0)

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

Difficulty: Very easy (0)