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

Difficulty: Medium

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

Difficulty: Medium

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

Difficulty: Medium

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

Difficulty: Easy