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

Difficulty: Very easy (0)

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

Difficulty: Easy (0)

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

Difficulty: Very easy (0)

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

Difficulty: Hard (0)