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

Difficulty: Hard (0)

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

Difficulty: Very easy (0)

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

Difficulty: Easy (0)

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

Difficulty: Hard (0)