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

Difficulty: Medium

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

Difficulty: Medium

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

Difficulty: Medium

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

Difficulty: Medium