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

Difficulty: Very hard (0)

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

Difficulty: Very hard (0)

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

Difficulty: Very hard (0)

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

Difficulty: Very easy (0)