11	9		3		12
6	9									2
			3					4		11	9
	3	6		12		7			1	4
2							10	7	9	8
7		10				9			3		11
4		9			7				11		2
	7	12	5	9							4
	8	3			11		12		7	1
9	4		1					8
	10									6	12
		2		10		8	1

Difficulty: Very easy (0)

	12				11			7	9
6		2		7	9					1
11	7			1			5			10	2
		5	7		10			9
	8		12			9	7		5
					8			12
			4			1
		10		9	4			5		8
			8			11		2	3
12	9			11			4			7	10
	3					5	12		6		9
		4	1			6				12

Difficulty: Hard (0)

		9					10	5		11
			2	11					3
10	7						4
		6		5		2			1	9	4
1					12	11		8
8							1	7	2	5
	12	8	10	3							7
			11		8	1					5
6	3	4			9		7		8
				1						4	9
		5					3	6
	2		3	8					11

Difficulty: Hard (0)

3		9			2				7	1
						4	11	3			2
		2							8		4
4	3					6			11		5
1			6	2						8	10
9		10		8					4
		3					6		2		8
11	6						1	10			7
2		7			3					5	9
10		11							5
7			4	12	10
	2	1				8			3		12

Difficulty: Easy (0)