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

Difficulty: Very easy (0)

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

Difficulty: Very easy (0)

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

Difficulty: Super easy (0)

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

Difficulty: Very hard (0)