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

Difficulty: Very easy (0)

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

Difficulty: Super easy (0)

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

Difficulty: Easy (0)

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

Difficulty: Super easy (0)