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

Difficulty: Very easy (0)

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

Difficulty: Very hard (0)

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

Difficulty: Very hard (0)

1						5
2			5
		8			7	2
	7	6			5		1
5		1			6	7
	2	7			8
				7			2
	1						4

Difficulty: Very easy (0)