16x16 hard t11d3p1.txt

Order 4: digits 16; houses 48, cells 256.

Grid.grid1: initial copying

pending={a2, a4, a5, b2, b6, b10, b12, b13, c6, c7, d10, d15, e3, e7, e16, f3, f5, f9, f12, f13, g7, g8, h3, h4, h5, h11, i3, j1, j5, j9, j11, j15, k5, k6, k8, k14, l1, l4, l5, l9, l11, l13, m3, m8, m11, m15, n6, o6, o9, o10, o12, o16, p2, p3, p8, p9, p14, p16}

deduce.grid1: naked-singles

deduce.grid1: hidden-singles

deduce.grid1.rowo. o11 is 6 by hidden-single.

pending={o11}

deduce.grid1: naked-singles

deduce.grid1: hidden-singles

deduce.grid1.rown. n16 is 6 by hidden-single.

pending={n16}

deduce.grid1: naked-singles

deduce.grid1: hidden-singles

deduce.grid1.col6. a6 is 6 by hidden-single.

pending={a6}

deduce.grid1: naked-singles

deduce.grid1: hidden-singles

deduce.grid1: naked-pairs

two's heap=.

grid1

1			4
		7	8
9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

1
		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1			4
		7
	10	11	12
13	14	15	16

1			4
		7
9	10	11	12
13	14	15	16



	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

1
		7	8
9	10	11	12
13	14	15	16


		7	8
9	10	11	12
13	14	15	16

1
		7	8
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
5		7
9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1
5		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
5		7
	10	11	12
13	14	15	16


5
	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

1
		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
5		7
9	10	11	12
13	14	15	16

1
5		7
9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1
5		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

1
5		7
	10	11	12
13	14	15	16

1
	6	7
9	10	11	12
13	14	15	16


5
	10	11	12
13	14	15	16


5	6
9	10	11	12
13	14	15	16

1		3
5		7
9	10	11	12
13	14	15	16

	2	3
5		7
9	10	11	12
13	14	15	16

1		3
		7
9	10	11	12
13	14	15	16

	2	3
		7
9	10	11	12
13	14	15	16

1			4
5		7	8
9	10	11	12
13	14	15	16

1
5		7	8
9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

1			4
5		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1		3
		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

1			4
5		7
	10	11	12
13	14	15	16


5
	10	11	12
13	14	15	16

			4
5
9	10	11	12
13	14	15	16

1		3
5		7	8
9	10	11	12
13	14	15	16

		3
5		7	8
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16


	6	7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

	2
	6	7
	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

		3
	6	7
	10	11	12
13	14	15	16

	2	3
5
	10	11	12
13	14	15	16

	2
5	6
	10	11	12
13	14	15	16

		3
5		7
9	10	11	12
13	14	15	16

	2	3
5		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

	2
		7
	10	11	12
13	14	15	16

	2
		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

	2
			8
	10	11	12
13	14	15	16

	2		4
		7	8
	10	11	12
13	14	15	16

			4
		7	8
	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

		3	4

	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

	2	3
5			8
	10	11	12
13	14	15	16

	2
5			8
	10	11	12
13	14	15	16

		3
5		7	8
9	10	11	12
13	14	15	16

	2	3	4
5		7	8
9	10	11	12
13	14	15	16

		3	4
		7	8
9	10	11	12
13	14	15	16

	2	3	4
		7
9	10	11	12
13	14	15	16


	6	7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

	2
5		7
	10	11	12
13	14	15	16

	2
		7
	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

		3
	6	7
	10	11	12
13	14	15	16

	2
5	6
	10	11	12
13	14	15	16

		3
5		7
	10	11	12
13	14	15	16

	2	3
5		7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

	2	3
		7
	10	11	12
13	14	15	16

1			4
5	6
9	10	11	12
13	14	15	16

1
5
9	10	11	12
13	14	15	16

1			4
5	6
	10	11	12
13	14	15	16

	2

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

	2	3

9	10	11	12
13	14	15	16

	2	3

9	10	11	12
13	14	15	16

1			4
5
	10	11	12
13	14	15	16

1			4

	10	11	12
13	14	15	16

	2
5			8
	10	11	12
13	14	15	16

	2		4
5			8
	10	11	12
13	14	15	16

1		3
			8
9	10	11	12
13	14	15	16

		3	4
			8
9	10	11	12
13	14	15	16

1		3	4
			8
9	10	11	12
13	14	15	16

		3	4

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

1			4

	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1			4

	10	11	12
13	14	15	16

			4
			8
	10	11	12
13	14	15	16

1
			8
9	10	11	12
13	14	15	16

			4
			8
9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16

	2	3
		7
9	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16

	2

	10	11	12
13	14	15	16

	2

	10	11	12
13	14	15	16

1		3
		7
9	10	11	12
13	14	15	16

1		3
		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16


5
	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16

			4
5
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

		3
5		7
9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16

		3	4

9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16


5		7	8
9	10	11	12
13	14	15	16

		3
5		7	8
9	10	11	12
13	14	15	16

		3

9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16

	2
5		7
9	10	11	12
13	14	15	16

	2		4
		7
9	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16

		3	4

9	10	11	12
13	14	15	16

		3

	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

		3

9	10	11	12
13	14	15	16

		3

	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

backtrack.grid1 → grid2: a11 guess 10 ∈ {10|11|12|13|14|15|16}

pending={a11}

deduce.grid2: naked-singles

deduce.grid2: hidden-singles

deduce.grid2: naked-pairs

two's heap=.

grid2

1			4
		7	8
9		11	12
13	14	15	16

			4

9		11	12
13	14	15	16

1
		7
9		11	12
13	14	15	16


		7
9		11	12
13	14	15	16

1			4
		7
		11	12
13	14	15	16

1			4
		7
9		11	12
13	14	15	16

			4

9		11	12
13	14	15	16

1
		7	8
9		11	12
13	14	15	16


		7	8
9		11	12
13	14	15	16

1
		7	8
9		11	12
13	14	15	16


		7
9		11	12
13	14	15	16

1
5		7
9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1
5		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
5		7
		11	12
13	14	15	16


5
		11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

1
		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
5		7
9	10	11	12
13	14	15	16

1
5		7
9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1
5		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

1
5		7
		11	12
13	14	15	16

1
	6	7
9		11	12
13	14	15	16


5
		11	12
13	14	15	16


5	6
9		11	12
13	14	15	16

1		3
5		7
9	10	11	12
13	14	15	16

	2	3
5		7
9	10	11	12
13	14	15	16

1		3
		7
9	10	11	12
13	14	15	16

	2	3
		7
9	10	11	12
13	14	15	16

1			4
5		7	8
9	10	11	12
13	14	15	16

1
5		7	8
9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

1			4
5		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1		3
		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

1			4
5		7
		11	12
13	14	15	16


5
		11	12
13	14	15	16

			4
5
9		11	12
13	14	15	16

1		3
5		7	8
9	10	11	12
13	14	15	16

		3
5		7	8
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16


	6	7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

	2
	6	7
	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

		3
	6	7
	10	11	12
13	14	15	16

	2	3
5
		11	12
13	14	15	16

	2
5	6
	10	11	12
13	14	15	16

		3
5		7
9	10	11	12
13	14	15	16

	2	3
5		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

	2
		7
	10	11	12
13	14	15	16

	2
		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

	2
			8
		11	12
13	14	15	16

	2		4
		7	8
	10	11	12
13	14	15	16

			4
		7	8
	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

		3	4

	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

	2	3
5			8
		11	12
13	14	15	16

	2
5			8
	10	11	12
13	14	15	16

		3
5		7	8
9	10	11	12
13	14	15	16

	2	3	4
5		7	8
9	10	11	12
13	14	15	16

		3	4
		7	8
9	10	11	12
13	14	15	16

	2	3	4
		7
9	10	11	12
13	14	15	16


	6	7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

	2
5		7
	10	11	12
13	14	15	16

	2
		7
	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

		3
	6	7
	10	11	12
13	14	15	16

	2
5	6
	10	11	12
13	14	15	16

		3
5		7
	10	11	12
13	14	15	16

	2	3
5		7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

	2	3
		7
	10	11	12
13	14	15	16

1			4
5	6
9	10	11	12
13	14	15	16

1
5
9	10	11	12
13	14	15	16

1			4
5	6
	10	11	12
13	14	15	16

	2

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

	2	3

9	10	11	12
13	14	15	16

	2	3

9	10	11	12
13	14	15	16

1			4
5
	10	11	12
13	14	15	16

1			4

	10	11	12
13	14	15	16

	2
5			8
		11	12
13	14	15	16

	2		4
5			8
	10	11	12
13	14	15	16

1		3
			8
9	10	11	12
13	14	15	16

		3	4
			8
9	10	11	12
13	14	15	16

1		3	4
			8
9	10	11	12
13	14	15	16

		3	4

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

1			4

	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1			4

	10	11	12
13	14	15	16

			4
			8
	10	11	12
13	14	15	16

1
			8
9	10	11	12
13	14	15	16

			4
			8
9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16

	2	3
		7
9	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16

	2

		11	12
13	14	15	16

	2

	10	11	12
13	14	15	16

1		3
		7
9	10	11	12
13	14	15	16

1		3
		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16


5
	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16

			4
5
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

		3
5		7
9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16

		3	4

9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16


5		7	8
9	10	11	12
13	14	15	16

		3
5		7	8
9	10	11	12
13	14	15	16

		3

9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16

	2
5		7
9	10	11	12
13	14	15	16

	2		4
		7
9	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16

		3	4

9	10	11	12
13	14	15	16

		3

		11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

		3

9	10	11	12
13	14	15	16

		3

		11	12
13	14	15	16



9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

backtrack.grid2 → grid3: b11 guess 5 ∈ {5|11|12|13|14|15|16}

pending={b11}

deduce.grid3: naked-singles

deduce.grid3: hidden-singles

deduce.grid3: naked-pairs

two's heap=.

grid3

1			4
		7	8
9		11	12
13	14	15	16

			4

9		11	12
13	14	15	16

1
		7
9		11	12
13	14	15	16


		7
9		11	12
13	14	15	16

1			4
		7
		11	12
13	14	15	16

1			4
		7
9		11	12
13	14	15	16

			4

9		11	12
13	14	15	16

1
		7	8
9		11	12
13	14	15	16


		7	8
9		11	12
13	14	15	16

1
		7	8
9		11	12
13	14	15	16


		7
9		11	12
13	14	15	16

1
		7
9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1
		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
		7
		11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
5		7
9	10	11	12
13	14	15	16

1
5		7
9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1
5		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

1
		7
		11	12
13	14	15	16

1
	6	7
9		11	12
13	14	15	16



		11	12
13	14	15	16


	6
9		11	12
13	14	15	16

1		3
5		7
9	10	11	12
13	14	15	16

	2	3
5		7
9	10	11	12
13	14	15	16

1		3
		7
9	10	11	12
13	14	15	16

	2	3
		7
9	10	11	12
13	14	15	16

1			4
5		7	8
9	10	11	12
13	14	15	16

1
5		7	8
9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

1			4
5		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1		3
		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

1			4
		7
		11	12
13	14	15	16



		11	12
13	14	15	16

			4

9		11	12
13	14	15	16

1		3
5		7	8
9	10	11	12
13	14	15	16

		3
5		7	8
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16


	6	7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

	2
	6	7
	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

		3
	6	7
	10	11	12
13	14	15	16

	2	3

		11	12
13	14	15	16

	2
5	6
	10	11	12
13	14	15	16

		3
5		7
9	10	11	12
13	14	15	16

	2	3
5		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

	2
		7
	10	11	12
13	14	15	16

	2
		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

	2
			8
		11	12
13	14	15	16

	2		4
		7	8
	10	11	12
13	14	15	16

			4
		7	8
	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

		3	4

	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

	2	3
			8
		11	12
13	14	15	16

	2
5			8
	10	11	12
13	14	15	16

		3
5		7	8
9	10	11	12
13	14	15	16

	2	3	4
5		7	8
9	10	11	12
13	14	15	16

		3	4
		7	8
9	10	11	12
13	14	15	16

	2	3	4
		7
9	10	11	12
13	14	15	16


	6	7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

	2
5		7
	10	11	12
13	14	15	16

	2
		7
	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

		3
	6	7
	10	11	12
13	14	15	16

	2
5	6
	10	11	12
13	14	15	16

		3
5		7
	10	11	12
13	14	15	16

	2	3
5		7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

	2	3
		7
	10	11	12
13	14	15	16

1			4
5	6
9	10	11	12
13	14	15	16

1
5
9	10	11	12
13	14	15	16

1			4
5	6
	10	11	12
13	14	15	16

	2

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

	2	3

9	10	11	12
13	14	15	16

	2	3

9	10	11	12
13	14	15	16

1			4
5
	10	11	12
13	14	15	16

1			4

	10	11	12
13	14	15	16

	2
			8
		11	12
13	14	15	16

	2		4
5			8
	10	11	12
13	14	15	16

1		3
			8
9	10	11	12
13	14	15	16

		3	4
			8
9	10	11	12
13	14	15	16

1		3	4
			8
9	10	11	12
13	14	15	16

		3	4

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

1			4

	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1			4

	10	11	12
13	14	15	16

			4
			8
	10	11	12
13	14	15	16

1
			8
9	10	11	12
13	14	15	16

			4
			8
9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16

	2	3
		7
9	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16

	2

		11	12
13	14	15	16

	2

	10	11	12
13	14	15	16

1		3
		7
9	10	11	12
13	14	15	16

1		3
		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16


5
	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16

			4
5
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

		3
5		7
9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16

		3	4

9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16


5		7	8
9	10	11	12
13	14	15	16

		3
5		7	8
9	10	11	12
13	14	15	16

		3

9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16

	2
5		7
9	10	11	12
13	14	15	16

	2		4
		7
9	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16

		3	4

9	10	11	12
13	14	15	16

		3

		11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

		3

9	10	11	12
13	14	15	16

		3

		11	12
13	14	15	16



9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

backtrack.grid3 → grid4: c11 guess 11 ∈ {11|12|13|14|15|16}

pending={c11}

deduce.grid4: naked-singles

deduce.grid4: hidden-singles

deduce.grid4: naked-pairs

two's heap=.

grid4

1			4
		7	8
9		11	12
13	14	15	16

			4

9		11	12
13	14	15	16

1
		7
9		11	12
13	14	15	16


		7
9		11	12
13	14	15	16

1			4
		7
			12
13	14	15	16

1			4
		7
9			12
13	14	15	16

			4

9			12
13	14	15	16

1
		7	8
9		11	12
13	14	15	16


		7	8
9		11	12
13	14	15	16

1
		7	8
9		11	12
13	14	15	16


		7
9		11	12
13	14	15	16

1
		7
9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1
		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
		7
			12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
5		7
9	10		12
13	14	15	16

1
5		7
9	10		12
13	14	15	16



9	10		12
13	14	15	16

1
5		7
	10		12
13	14	15	16


		7
9	10		12
13	14	15	16

		3
		7
9	10		12
13	14	15	16

1
		7
			12
13	14	15	16

1
	6	7
9			12
13	14	15	16


	6
9			12
13	14	15	16

1		3
5		7
9	10		12
13	14	15	16

	2	3
5		7
9	10		12
13	14	15	16

1		3
		7
9	10		12
13	14	15	16

	2	3
		7
9	10		12
13	14	15	16

1			4
5		7	8
9	10	11	12
13	14	15	16

1
5		7	8
9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

1			4
5		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1		3
		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

1			4
		7
			12
13	14	15	16



			12
13	14	15	16

			4

9			12
13	14	15	16

1		3
5		7	8
9	10	11	12
13	14	15	16

		3
5		7	8
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16


	6	7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

	2
	6	7
	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

		3
	6	7
	10	11	12
13	14	15	16

	2	3

			12
13	14	15	16

	2
5	6
	10	11	12
13	14	15	16

		3
5		7
9	10	11	12
13	14	15	16

	2	3
5		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

	2
		7
	10	11	12
13	14	15	16

	2
		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

	2
			8
			12
13	14	15	16

	2		4
		7	8
	10	11	12
13	14	15	16

			4
		7	8
	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

		3	4

	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

	2	3
			8
			12
13	14	15	16

	2
5			8
	10	11	12
13	14	15	16

		3
5		7	8
9	10	11	12
13	14	15	16

	2	3	4
5		7	8
9	10	11	12
13	14	15	16

		3	4
		7	8
9	10	11	12
13	14	15	16

	2	3	4
		7
9	10	11	12
13	14	15	16


	6	7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

	2
5		7
	10	11	12
13	14	15	16

	2
		7
	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

		3
	6	7
	10	11	12
13	14	15	16

	2
5	6
	10	11	12
13	14	15	16

		3
5		7
	10	11	12
13	14	15	16

	2	3
5		7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

	2	3
		7
	10	11	12
13	14	15	16

1			4
5	6
9	10	11	12
13	14	15	16

1
5
9	10	11	12
13	14	15	16

1			4
5	6
	10	11	12
13	14	15	16

	2

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

	2	3

9	10	11	12
13	14	15	16

	2	3

9	10	11	12
13	14	15	16

1			4
5
	10	11	12
13	14	15	16

1			4

	10	11	12
13	14	15	16

	2
			8
			12
13	14	15	16

	2		4
5			8
	10	11	12
13	14	15	16

1		3
			8
9	10	11	12
13	14	15	16

		3	4
			8
9	10	11	12
13	14	15	16

1		3	4
			8
9	10	11	12
13	14	15	16

		3	4

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

1			4

	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1			4

	10	11	12
13	14	15	16

			4
			8
	10	11	12
13	14	15	16

1
			8
9	10	11	12
13	14	15	16

			4
			8
9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16

	2	3
		7
9	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16

	2

			12
13	14	15	16

	2

	10	11	12
13	14	15	16

1		3
		7
9	10	11	12
13	14	15	16

1		3
		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16


5
	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16

			4
5
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

		3
5		7
9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16

		3	4

9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16


5		7	8
9	10	11	12
13	14	15	16

		3
5		7	8
9	10	11	12
13	14	15	16

		3

9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16

	2
5		7
9	10	11	12
13	14	15	16

	2		4
		7
9	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16

		3	4

9	10	11	12
13	14	15	16

		3

			12
13	14	15	16

			4

9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

		3

9	10	11	12
13	14	15	16

		3

			12
13	14	15	16



9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

backtrack.grid4 → grid5: d11 guess 12 ∈ {12|13|14|15|16}

pending={d11}

deduce.grid5: naked-singles

deduce.grid5: hidden-singles

deduce.grid5: naked-pairs

two's heap=.

grid5

1			4
		7	8
9		11	12
13	14	15	16

			4

9		11	12
13	14	15	16

1
		7
9		11	12
13	14	15	16


		7
9		11	12
13	14	15	16

1			4
		7

13	14	15	16

1			4
		7
9
13	14	15	16

			4

9
13	14	15	16

1
		7	8
9		11	12
13	14	15	16


		7	8
9		11	12
13	14	15	16

1
		7	8
9		11	12
13	14	15	16


		7
9		11	12
13	14	15	16

1
		7
9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1
		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
		7

13	14	15	16


		7
9	10	11	12
13	14	15	16

1
		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
5		7
9	10		12
13	14	15	16

1
5		7
9	10		12
13	14	15	16



9	10		12
13	14	15	16

1
5		7
	10		12
13	14	15	16


		7
9	10		12
13	14	15	16

		3
		7
9	10		12
13	14	15	16

1
		7

13	14	15	16

1
	6	7
9
13	14	15	16


	6
9
13	14	15	16

1		3
5		7
9	10		12
13	14	15	16

	2	3
5		7
9	10		12
13	14	15	16

1		3
		7
9	10		12
13	14	15	16

	2	3
		7
9	10		12
13	14	15	16

1			4
5		7	8
9	10	11
13	14	15	16

1
5		7	8
9	10	11
13	14	15	16

			4

9	10	11
13	14	15	16

1			4
5		7
	10	11
13	14	15	16


		7
9	10	11
13	14	15	16


		7
9	10	11
13	14	15	16

1		3
		7
9	10	11
13	14	15	16

		3
		7
9	10	11
13	14	15	16

1			4
		7

13	14	15	16

			4

9
13	14	15	16

1		3
5		7	8
9	10	11
13	14	15	16

		3
5		7	8
9	10	11
13	14	15	16

		3
		7
9	10	11
13	14	15	16


	6	7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

	2
	6	7
	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

		3
	6	7
	10	11	12
13	14	15	16

	2	3


13	14	15	16

	2
5	6
	10	11	12
13	14	15	16

		3
5		7
9	10	11	12
13	14	15	16

	2	3
5		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

	2
		7
	10	11	12
13	14	15	16

	2
		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

	2
			8

13	14	15	16

	2		4
		7	8
	10	11	12
13	14	15	16

			4
		7	8
	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

		3	4

	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

	2	3
			8

13	14	15	16

	2
5			8
	10	11	12
13	14	15	16

		3
5		7	8
9	10	11	12
13	14	15	16

	2	3	4
5		7	8
9	10	11	12
13	14	15	16

		3	4
		7	8
9	10	11	12
13	14	15	16

	2	3	4
		7
9	10	11	12
13	14	15	16


	6	7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

	2
5		7
	10	11	12
13	14	15	16

	2
		7
	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

		3
	6	7
	10	11	12
13	14	15	16

	2
5	6
	10	11	12
13	14	15	16

		3
5		7
	10	11	12
13	14	15	16

	2	3
5		7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

	2	3
		7
	10	11	12
13	14	15	16

1			4
5	6
9	10	11	12
13	14	15	16

1
5
9	10	11	12
13	14	15	16

1			4
5	6
	10	11	12
13	14	15	16

	2

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

	2	3

9	10	11	12
13	14	15	16

	2	3

9	10	11	12
13	14	15	16

1			4
5
	10	11	12
13	14	15	16

1			4

	10	11	12
13	14	15	16

	2
			8

13	14	15	16

	2		4
5			8
	10	11	12
13	14	15	16

1		3
			8
9	10	11	12
13	14	15	16

		3	4
			8
9	10	11	12
13	14	15	16

1		3	4
			8
9	10	11	12
13	14	15	16

		3	4

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

1			4

	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1			4

	10	11	12
13	14	15	16

			4
			8
	10	11	12
13	14	15	16

1
			8
9	10	11	12
13	14	15	16

			4
			8
9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16

	2	3
		7
9	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16

	2


13	14	15	16

	2

	10	11	12
13	14	15	16

1		3
		7
9	10	11	12
13	14	15	16

1		3
		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16


5
	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16

			4
5
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

		3
5		7
9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16

		3	4

9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16


5		7	8
9	10	11	12
13	14	15	16

		3
5		7	8
9	10	11	12
13	14	15	16

		3

9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16

	2
5		7
9	10	11	12
13	14	15	16

	2		4
		7
9	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16

		3	4

9	10	11	12
13	14	15	16

		3


13	14	15	16

			4

9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

		3

9	10	11	12
13	14	15	16

		3


13	14	15	16



9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

backtrack.grid5 → grid6: k11 guess 2 ∈ {2|13|14|15|16}

pending={k11}

deduce.grid6: naked-singles

deduce.grid6: hidden-singles

deduce.grid6: naked-pairs

two's heap=.

grid6

1			4
		7	8
9		11	12
13	14	15	16

			4

9		11	12
13	14	15	16

1
		7
9		11	12
13	14	15	16


		7
9		11	12
13	14	15	16

1			4
		7

13	14	15	16

1			4
		7
9
13	14	15	16

			4

9
13	14	15	16

1
		7	8
9		11	12
13	14	15	16


		7	8
9		11	12
13	14	15	16

1
		7	8
9		11	12
13	14	15	16


		7
9		11	12
13	14	15	16

1
		7
9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1
		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
		7

13	14	15	16


		7
9	10	11	12
13	14	15	16

1
		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
5		7
9	10		12
13	14	15	16

1
5		7
9	10		12
13	14	15	16



9	10		12
13	14	15	16

1
5		7
	10		12
13	14	15	16


		7
9	10		12
13	14	15	16

		3
		7
9	10		12
13	14	15	16

1
		7

13	14	15	16

1
	6	7
9
13	14	15	16


	6
9
13	14	15	16

1		3
5		7
9	10		12
13	14	15	16

	2	3
5		7
9	10		12
13	14	15	16

1		3
		7
9	10		12
13	14	15	16

	2	3
		7
9	10		12
13	14	15	16

1			4
5		7	8
9	10	11
13	14	15	16

1
5		7	8
9	10	11
13	14	15	16

			4

9	10	11
13	14	15	16

1			4
5		7
	10	11
13	14	15	16


		7
9	10	11
13	14	15	16


		7
9	10	11
13	14	15	16

1		3
		7
9	10	11
13	14	15	16

		3
		7
9	10	11
13	14	15	16

1			4
		7

13	14	15	16

			4

9
13	14	15	16

1		3
5		7	8
9	10	11
13	14	15	16

		3
5		7	8
9	10	11
13	14	15	16

		3
		7
9	10	11
13	14	15	16


	6	7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

	2
	6	7
	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

		3
	6	7
	10	11	12
13	14	15	16

		3


13	14	15	16

	2
5	6
	10	11	12
13	14	15	16

		3
5		7
9	10	11	12
13	14	15	16

	2	3
5		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

	2
		7
	10	11	12
13	14	15	16

	2
		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


			8

13	14	15	16

	2		4
		7	8
	10	11	12
13	14	15	16

			4
		7	8
	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

		3	4

	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

		3
			8

13	14	15	16

	2
5			8
	10	11	12
13	14	15	16

		3
5		7	8
9	10	11	12
13	14	15	16

	2	3	4
5		7	8
9	10	11	12
13	14	15	16

		3	4
		7	8
9	10	11	12
13	14	15	16

	2	3	4
		7
9	10	11	12
13	14	15	16


	6	7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

	2
5		7
	10	11	12
13	14	15	16

	2
		7
	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

		3
	6	7
	10	11	12
13	14	15	16

	2
5	6
	10	11	12
13	14	15	16

		3
5		7
	10	11	12
13	14	15	16

	2	3
5		7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

	2	3
		7
	10	11	12
13	14	15	16

1			4
5	6
9	10	11	12
13	14	15	16

1
5
9	10	11	12
13	14	15	16

1			4
5	6
	10	11	12
13	14	15	16

	2

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

	2	3

9	10	11	12
13	14	15	16

	2	3

9	10	11	12
13	14	15	16

1			4
5
	10	11	12
13	14	15	16

1			4

	10	11	12
13	14	15	16


			8

13	14	15	16

			4
5			8
	10	11	12
13	14	15	16

1		3
			8
9	10	11	12
13	14	15	16

		3	4
			8
9	10	11	12
13	14	15	16

1		3	4
			8
9	10	11	12
13	14	15	16

		3	4

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

1			4

	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1			4

	10	11	12
13	14	15	16

			4
			8
	10	11	12
13	14	15	16

1
			8
9	10	11	12
13	14	15	16

			4
			8
9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16



	10	11	12
13	14	15	16

1		3
		7
9	10	11	12
13	14	15	16

1		3
		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16


5
	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16

			4
5
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

		3
5		7
9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16

		3	4

9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16


5		7	8
9	10	11	12
13	14	15	16

		3
5		7	8
9	10	11	12
13	14	15	16

		3

9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16

	2
5		7
9	10	11	12
13	14	15	16

	2		4
		7
9	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16

		3	4

9	10	11	12
13	14	15	16

		3


13	14	15	16

			4

9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

		3

9	10	11	12
13	14	15	16

		3


13	14	15	16



9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

backtrack.grid6 → grid7: e11 guess 3 ∈ {3|13|14|15|16}

pending={e11}

deduce.grid7: naked-singles

deduce.grid7: hidden-singles

deduce.grid7: naked-pairs

two's heap=.

grid7

1			4
		7	8
9		11	12
13	14	15	16

			4

9		11	12
13	14	15	16

1
		7
9		11	12
13	14	15	16


		7
9		11	12
13	14	15	16

1			4
		7

13	14	15	16

1			4
		7
9
13	14	15	16

			4

9
13	14	15	16

1
		7	8
9		11	12
13	14	15	16


		7	8
9		11	12
13	14	15	16

1
		7	8
9		11	12
13	14	15	16


		7
9		11	12
13	14	15	16

1
		7
9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1
		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
		7

13	14	15	16


		7
9	10	11	12
13	14	15	16

1
		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
5		7
9	10		12
13	14	15	16

1
5		7
9	10		12
13	14	15	16



9	10		12
13	14	15	16

1
5		7
	10		12
13	14	15	16


		7
9	10		12
13	14	15	16

		3
		7
9	10		12
13	14	15	16

1
		7

13	14	15	16

1
	6	7
9
13	14	15	16


	6
9
13	14	15	16

1		3
5		7
9	10		12
13	14	15	16

	2	3
5		7
9	10		12
13	14	15	16

1		3
		7
9	10		12
13	14	15	16

	2	3
		7
9	10		12
13	14	15	16

1			4
5		7	8
9	10	11
13	14	15	16

1
5		7	8
9	10	11
13	14	15	16

			4

9	10	11
13	14	15	16

1			4
5		7
	10	11
13	14	15	16


		7
9	10	11
13	14	15	16


		7
9	10	11
13	14	15	16

1		3
		7
9	10	11
13	14	15	16

		3
		7
9	10	11
13	14	15	16

1			4
		7

13	14	15	16

			4

9
13	14	15	16

1		3
5		7	8
9	10	11
13	14	15	16

		3
5		7	8
9	10	11
13	14	15	16

		3
		7
9	10	11
13	14	15	16


	6	7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

	2
	6	7
	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16


	6	7
	10	11	12
13	14	15	16

	2
5	6
	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

	2
5		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

	2
		7
	10	11	12
13	14	15	16

	2
		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


			8

13	14	15	16

	2		4
		7	8
	10	11	12
13	14	15	16

			4
		7	8
	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

		3	4

	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


			8

13	14	15	16

	2
5			8
	10	11	12
13	14	15	16

		3
5		7	8
9	10	11	12
13	14	15	16

	2	3	4
5		7	8
9	10	11	12
13	14	15	16

		3	4
		7	8
9	10	11	12
13	14	15	16

	2	3	4
		7
9	10	11	12
13	14	15	16


	6	7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

	2
5		7
	10	11	12
13	14	15	16

	2
		7
	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16


	6	7
	10	11	12
13	14	15	16

	2
5	6
	10	11	12
13	14	15	16

		3
5		7
	10	11	12
13	14	15	16

	2	3
5		7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

	2	3
		7
	10	11	12
13	14	15	16

1			4
5	6
9	10	11	12
13	14	15	16

1
5
9	10	11	12
13	14	15	16

1			4
5	6
	10	11	12
13	14	15	16

	2

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

	2	3

9	10	11	12
13	14	15	16

	2	3

9	10	11	12
13	14	15	16

1			4
5
	10	11	12
13	14	15	16

1			4

	10	11	12
13	14	15	16


			8

13	14	15	16

			4
5			8
	10	11	12
13	14	15	16

1		3
			8
9	10	11	12
13	14	15	16

		3	4
			8
9	10	11	12
13	14	15	16

1		3	4
			8
9	10	11	12
13	14	15	16

		3	4

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

1			4

	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1			4

	10	11	12
13	14	15	16

			4
			8
	10	11	12
13	14	15	16

1
			8
9	10	11	12
13	14	15	16

			4
			8
9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16



	10	11	12
13	14	15	16

1		3
		7
9	10	11	12
13	14	15	16

1		3
		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16


5
	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16

			4
5
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

		3
5		7
9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16

		3	4

9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16


5		7	8
9	10	11	12
13	14	15	16

		3
5		7	8
9	10	11	12
13	14	15	16

		3

9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16

	2
5		7
9	10	11	12
13	14	15	16

	2		4
		7
9	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16

		3	4

9	10	11	12
13	14	15	16




13	14	15	16

			4

9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

		3

9	10	11	12
13	14	15	16




13	14	15	16



9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

backtrack.grid7 → grid8: n11 guess 13 ∈ {13|14|15|16}

pending={n11}

deduce.grid8: naked-singles

deduce.grid8: hidden-singles

deduce.grid8: naked-pairs

two's heap=.

grid8

1			4
		7	8
9		11	12
13	14	15	16

			4

9		11	12
13	14	15	16

1
		7
9		11	12
13	14	15	16


		7
9		11	12
13	14	15	16

1			4
		7

13	14	15	16

1			4
		7
9
13	14	15	16

			4

9
13	14	15	16

1
		7	8
9		11	12
13	14	15	16


		7	8
9		11	12
13	14	15	16

1
		7	8
9		11	12
13	14	15	16


		7
9		11	12
13	14	15	16

1
		7
9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1
		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
		7

13	14	15	16


		7
9	10	11	12
13	14	15	16

1
		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
5		7
9	10		12
13	14	15	16

1
5		7
9	10		12
13	14	15	16



9	10		12
13	14	15	16

1
5		7
	10		12
13	14	15	16


		7
9	10		12
13	14	15	16

		3
		7
9	10		12
13	14	15	16

1
		7

13	14	15	16

1
	6	7
9
13	14	15	16


	6
9
13	14	15	16

1		3
5		7
9	10		12
13	14	15	16

	2	3
5		7
9	10		12
13	14	15	16

1		3
		7
9	10		12
13	14	15	16

	2	3
		7
9	10		12
13	14	15	16

1			4
5		7	8
9	10	11
13	14	15	16

1
5		7	8
9	10	11
13	14	15	16

			4

9	10	11
13	14	15	16

1			4
5		7
	10	11
13	14	15	16


		7
9	10	11
13	14	15	16


		7
9	10	11
13	14	15	16

1		3
		7
9	10	11
13	14	15	16

		3
		7
9	10	11
13	14	15	16

1			4
		7

13	14	15	16

			4

9
13	14	15	16

1		3
5		7	8
9	10	11
13	14	15	16

		3
5		7	8
9	10	11
13	14	15	16

		3
		7
9	10	11
13	14	15	16


	6	7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

	2
	6	7
	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16


	6	7
	10	11	12
13	14	15	16

	2
5	6
	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

	2
5		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

	2
		7
	10	11	12
13	14	15	16

	2
		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


		8

14	15	16

	2		4
		7	8
	10	11	12
13	14	15	16

			4
		7	8
	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

		3	4

	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


		8

14	15	16

	2
5			8
	10	11	12
13	14	15	16

		3
5		7	8
9	10	11	12
13	14	15	16

	2	3	4
5		7	8
9	10	11	12
13	14	15	16

		3	4
		7	8
9	10	11	12
13	14	15	16

	2	3	4
		7
9	10	11	12
13	14	15	16


	6	7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

	2
5		7
	10	11	12
13	14	15	16

	2
		7
	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16


	6	7
	10	11	12
13	14	15	16

	2
5	6
	10	11	12
13	14	15	16

		3
5		7
	10	11	12
13	14	15	16

	2	3
5		7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

	2	3
		7
	10	11	12
13	14	15	16

1			4
5	6
9	10	11	12
13	14	15	16

1
5
9	10	11	12
13	14	15	16

1			4
5	6
	10	11	12
13	14	15	16

	2

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

	2	3

9	10	11	12
13	14	15	16

	2	3

9	10	11	12
13	14	15	16

1			4
5
	10	11	12
13	14	15	16

1			4

	10	11	12
13	14	15	16


		8

14	15	16

			4
5			8
	10	11	12
13	14	15	16

1		3
			8
9	10	11	12
13	14	15	16

		3	4
			8
9	10	11	12
13	14	15	16

1		3	4
			8
9	10	11	12
13	14	15	16

		3	4

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

1			4

	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1			4

	10	11	12
13	14	15	16

			4
			8
	10	11	12
13	14	15	16

1
			8
9	10	11	12
13	14	15	16

			4
			8
9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16



	10	11	12
13	14	15	16

1		3
		7
9	10	11	12
13	14	15	16

1		3
		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16


5
	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16

			4
5
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

		3
5		7
9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

		4

10	11	12
14	15	16

		3	4

9	10	11	12
	14	15	16

			4

9	10	11	12
	14	15	16

		3
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16


5		7	8
9	10	11	12
	14	15	16

		3
5		7	8
9	10	11	12
	14	15	16

		3

9	10	11	12
	14	15	16


5		7
	10	11	12
	14	15	16

	2
		7
9	10	11	12
	14	15	16

	2
5		7
9	10	11	12
	14	15	16

	2		4
		7
9	10	11	12
	14	15	16

		4

10	11	12
14	15	16

		3	4

9	10	11	12
	14	15	16

			4

9	10	11	12
	14	15	16

		3
		7
9	10	11	12
	14	15	16

		3	4
		7
9	10	11	12
	14	15	16

		3	4
		7
9	10	11	12
	14	15	16

1

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

		3

9	10	11	12
	14	15	16




14	15	16



9	10	11	12
	14	15	16

		3
		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

backtrack.grid8 → grid9: p11 guess 14 ∈ {14|15|16}

pending={p11}

deduce.grid9: naked-singles

deduce.grid9: hidden-singles

deduce.grid9: naked-pairs

two's heap=.

grid9

1			4
		7	8
9		11	12
13	14	15	16

			4

9		11	12
13	14	15	16

1
		7
9		11	12
13	14	15	16


		7
9		11	12
13	14	15	16

1			4
		7

13	14	15	16

1			4
		7
9
13	14	15	16

			4

9
13	14	15	16

1
		7	8
9		11	12
13	14	15	16


		7	8
9		11	12
13	14	15	16

1
		7	8
9		11	12
13	14	15	16


		7
9		11	12
13	14	15	16

1
		7
9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1
		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
		7

13	14	15	16


		7
9	10	11	12
13	14	15	16

1
		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
5		7
9	10		12
13	14	15	16

1
5		7
9	10		12
13	14	15	16



9	10		12
13	14	15	16

1
5		7
	10		12
13	14	15	16


		7
9	10		12
13	14	15	16

		3
		7
9	10		12
13	14	15	16

1
		7

13	14	15	16

1
	6	7
9
13	14	15	16


	6
9
13	14	15	16

1		3
5		7
9	10		12
13	14	15	16

	2	3
5		7
9	10		12
13	14	15	16

1		3
		7
9	10		12
13	14	15	16

	2	3
		7
9	10		12
13	14	15	16

1			4
5		7	8
9	10	11
13	14	15	16

1
5		7	8
9	10	11
13	14	15	16

			4

9	10	11
13	14	15	16

1			4
5		7
	10	11
13	14	15	16


		7
9	10	11
13	14	15	16


		7
9	10	11
13	14	15	16

1		3
		7
9	10	11
13	14	15	16

		3
		7
9	10	11
13	14	15	16

1			4
		7

13	14	15	16

			4

9
13	14	15	16

1		3
5		7	8
9	10	11
13	14	15	16

		3
5		7	8
9	10	11
13	14	15	16

		3
		7
9	10	11
13	14	15	16


	6	7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

	2
	6	7
	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16


	6	7
	10	11	12
13	14	15	16

	2
5	6
	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

	2
5		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

	2
		7
	10	11	12
13	14	15	16

	2
		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


			8

		15	16

	2		4
		7	8
	10	11	12
13	14	15	16

			4
		7	8
	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

		3	4

	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


			8

		15	16

	2
5			8
	10	11	12
13	14	15	16

		3
5		7	8
9	10	11	12
13	14	15	16

	2	3	4
5		7	8
9	10	11	12
13	14	15	16

		3	4
		7	8
9	10	11	12
13	14	15	16

	2	3	4
		7
9	10	11	12
13	14	15	16


	6	7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

	2
5		7
	10	11	12
13	14	15	16

	2
		7
	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16


	6	7
	10	11	12
13	14	15	16

	2
5	6
	10	11	12
13	14	15	16

		3
5		7
	10	11	12
13	14	15	16

	2	3
5		7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

	2	3
		7
	10	11	12
13	14	15	16

1			4
5	6
9	10	11	12
13	14	15	16

1
5
9	10	11	12
13	14	15	16

1			4
5	6
	10	11	12
13	14	15	16

	2

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

	2	3

9	10	11	12
13	14	15	16

	2	3

9	10	11	12
13	14	15	16

1			4
5
	10	11	12
13	14	15	16

1			4

	10	11	12
13	14	15	16


			8

		15	16

			4
5			8
	10	11	12
13	14	15	16

1		3
			8
9	10	11	12
13	14	15	16

		3	4
			8
9	10	11	12
13	14	15	16

1		3	4
			8
9	10	11	12
13	14	15	16

		3	4

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

1			4

	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1			4

	10	11	12
13	14	15	16

			4
			8
	10	11	12
13	14	15	16

1
			8
9	10	11	12
13	14	15	16

			4
			8
9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16



	10	11	12
13	14	15	16

1		3
		7
9	10	11	12
13	14	15	16

1		3
		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16


5
	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16

			4
5
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

		3
5		7
9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

		4

10	11	12
	15	16

		3	4

9	10	11	12
		15	16

			4

9	10	11	12
		15	16

		3
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16


5		7	8
9	10	11	12
	14	15	16

		3
5		7	8
9	10	11	12
	14	15	16

		3

9	10	11	12
	14	15	16


5		7
	10	11	12
	14	15	16

	2
		7
9	10	11	12
	14	15	16

	2
5		7
9	10	11	12
	14	15	16

	2		4
		7
9	10	11	12
	14	15	16

		4

10	11	12
	15	16

		3	4

9	10	11	12
		15	16

			4

9	10	11	12
		15	16

		3
		7
9	10	11	12
	14	15	16

		3	4
		7
9	10	11	12
	14	15	16

		3	4
		7
9	10	11	12
	14	15	16

1

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16


		7
9	10	11	12
13		15	16


		7
	10	11	12
13		15	16


		7
9	10	11	12
13		15	16


		7
9	10	11	12
13		15	16


		7
9	10	11	12
13		15	16

		3

9	10	11	12
		15	16



9	10	11	12
		15	16

		3
		7
9	10	11	12
13		15	16

		3
		7
9	10	11	12
13		15	16

backtrack.grid9 → grid10: f11 guess 8 ∈ {8|15|16}

pending={f11}

deduce.grid10: naked-singles

deduce.grid10: hidden-singles

deduce.grid10: naked-pairs

two's heap=g11 {15|16}, i11 {15|16}.

grid10

1			4
		7	8
9		11	12
13	14	15	16

			4

9		11	12
13	14	15	16

1
		7
9		11	12
13	14	15	16


		7
9		11	12
13	14	15	16

1			4
		7

13	14	15	16

1			4
		7
9
13	14	15	16

			4

9
13	14	15	16

1
		7	8
9		11	12
13	14	15	16


		7	8
9		11	12
13	14	15	16

1
		7	8
9		11	12
13	14	15	16


		7
9		11	12
13	14	15	16

1
		7
9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1
		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
		7

13	14	15	16


		7
9	10	11	12
13	14	15	16

1
		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

1
5		7
9	10		12
13	14	15	16

1
5		7
9	10		12
13	14	15	16



9	10		12
13	14	15	16

1
5		7
	10		12
13	14	15	16


		7
9	10		12
13	14	15	16

		3
		7
9	10		12
13	14	15	16

1
		7

13	14	15	16

1
	6	7
9
13	14	15	16


	6
9
13	14	15	16

1		3
5		7
9	10		12
13	14	15	16

	2	3
5		7
9	10		12
13	14	15	16

1		3
		7
9	10		12
13	14	15	16

	2	3
		7
9	10		12
13	14	15	16

1			4
5		7	8
9	10	11
13	14	15	16

1
5		7	8
9	10	11
13	14	15	16

			4

9	10	11
13	14	15	16

1			4
5		7
	10	11
13	14	15	16


		7
9	10	11
13	14	15	16


		7
9	10	11
13	14	15	16

1		3
		7
9	10	11
13	14	15	16

		3
		7
9	10	11
13	14	15	16

1			4
		7

13	14	15	16

			4

9
13	14	15	16

1		3
5		7	8
9	10	11
13	14	15	16

		3
5		7	8
9	10	11
13	14	15	16

		3
		7
9	10	11
13	14	15	16


	6	7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

	2
	6	7
	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16


	6	7
	10	11	12
13	14	15	16

	2
5	6
	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

	2
5		7
9	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

	2
		7
	10	11	12
13	14	15	16

	2
		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

		3	4

	10	11	12
13	14	15	16

	2		4
		7
	10	11	12
13	14	15	16

	2
		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16




		15	16

	2
5
	10	11	12
13	14	15	16

		3
5		7	8
9	10	11	12
13	14	15	16

	2	3	4
5		7	8
9	10	11	12
13	14	15	16

		3	4
		7	8
9	10	11	12
13	14	15	16

	2	3	4
		7
9	10	11	12
13	14	15	16


	6	7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16

	2
5		7
	10	11	12
13	14	15	16

	2
		7
	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16


	6	7
	10	11	12
13	14	15	16

	2
5	6
	10	11	12
13	14	15	16

		3
5		7
	10	11	12
13	14	15	16

	2	3
5		7
	10	11	12
13	14	15	16

		3
		7
	10	11	12
13	14	15	16

	2	3
		7
	10	11	12
13	14	15	16

1			4
5	6
9	10	11	12
13	14	15	16

1
5
9	10	11	12
13	14	15	16

1			4
5	6
	10	11	12
13	14	15	16

	2

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

	2	3

9	10	11	12
13	14	15	16

	2	3

9	10	11	12
13	14	15	16

1			4
5
	10	11	12
13	14	15	16

1			4

	10	11	12
13	14	15	16




		15	16

			4
5			8
	10	11	12
13	14	15	16

1		3
			8
9	10	11	12
13	14	15	16

		3	4
			8
9	10	11	12
13	14	15	16

1		3	4
			8
9	10	11	12
13	14	15	16

		3	4

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

1			4

	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1			4

	10	11	12
13	14	15	16

			4
			8
	10	11	12
13	14	15	16

1
			8
9	10	11	12
13	14	15	16

			4
			8
9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16



	10	11	12
13	14	15	16

1		3
		7
9	10	11	12
13	14	15	16

1		3
		7
9	10	11	12
13	14	15	16

		3
		7
9	10	11	12
13	14	15	16


5
	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16


		7
	10	11	12
13	14	15	16

			4

	10	11	12
13	14	15	16

			4
5
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16

			4
		7
	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

		3
5		7
9	10	11	12
13	14	15	16


5		7
	10	11	12
13	14	15	16


		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16


5		7
9	10	11	12
13	14	15	16

		4

10	11	12
	15	16

		3	4

9	10	11	12
		15	16

			4

9	10	11	12
		15	16

		3
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16

		3	4
		7
9	10	11	12
13	14	15	16


5		7	8
9	10	11	12
	14	15	16

		3
5		7	8
9	10	11	12
	14	15	16

		3

9	10	11	12
	14	15	16


5		7
	10	11	12
	14	15	16

	2
		7
9	10	11	12
	14	15	16

	2
5		7
9	10	11	12
	14	15	16

	2		4
		7
9	10	11	12
	14	15	16

		4

10	11	12
	15	16

		3	4

9	10	11	12
		15	16

			4

9	10	11	12
		15	16

		3
		7
9	10	11	12
	14	15	16

		3	4
		7
9	10	11	12
	14	15	16

		3	4
		7
9	10	11	12
	14	15	16

1

9	10	11	12
13	14	15	16

1

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

1

	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16



9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16

			4

9	10	11	12
13	14	15	16


		7
9	10	11	12
13		15	16


		7
	10	11	12
13		15	16


		7
9	10	11	12
13		15	16


		7
9	10	11	12
13		15	16


		7
9	10	11	12
13		15	16

		3

9	10	11	12
		15	16



9	10	11	12
		15	16

		3
		7
9	10	11	12
13		15	16

		3
		7
9	10	11	12
13		15	16

backtrack.grid10 → grid11: g11 guess 15 ∈ {15|16}

…

backtrack.grid95 → grid96: e2 guess 14 ∈ {14|16}

pending={e2}

deduce.grid96: naked-singles

f2 is 16 by naked-single. pending={f2}
f7 is 14 by naked-single. pending={f7}

deduce.grid96: hidden-singles

deduce.grid96: naked-pairs

two's heap=p6 {7|9}, l15 {10|12}, m2 {9|12}, j14 {9|16}, l8 {10|13}, m13 {7|16}, j16 {13|14}, e6 {12|16}, l14 {12|16}, j3 {11|16}, i16 {13|14}, e5 {12|16}, o13 {10|16}, k3 {12|16}.

Naked-pair {13|14} in cells {i16, j16} contained within {col16, box12}, updating cells {j14, k15, l14, l15}:

grid96



			12
			16



			12
			16



9		12
13	15

2

		12
14	15



9		12
	14



9			12
13

	2


13		15




13	14



9	10
13		15



		11
			16



9		11
	14		16



9	10
13		16



	10
13		15



9
			16




13	14



9	10
		16



9	10	12



			12
			16



9	10	12



		11	12
			16


		7
		11	12
			16


		7
	10		12
13			16



	10
13



			12
			16



	10		12


	7
9
		16



9			12



			12
	14		16


		7
9			12
	14		16


		7

			16


	7
10
		16

	2

			12
			16


	7
10		12
		16

	2		4

	10


	7
10
		16

			4

	10		12



9	10	12



			12
		15	16



9	10	12
13		16

			4

	10
13		15



	10
			16



9			12
			16

		4

9	10	12


		7
9	10


		7
9


		7
9	10

backtrack.grid96 → grid97: e5 guess 12 ∈ {12|16}

pending={e5}

deduce.grid97: naked-singles

e6 is 16 by naked-single. pending={e6}

deduce.grid97: hidden-singles

deduce.grid97: naked-pairs

two's heap=p6 {7|9}, l15 {10|12}, m2 {9|12}, l8 {10|13}, m13 {7|16}, n5 {2|16}, i16 {13|14}, j3 {11|16}, j16 {13|14}, m5 {14|16}, k3 {12|16}, j14 {9|16}, o5 {15|16}, l14 {12|16}, o13 {10|16}.

Naked-pair {13|14} in cells {i16, j16} contained within {col16, box12}, updating cells {j14, k15, l14, l15}:

grid97



9		12
13	15

	2


	14	15



9		12
	14



9			12
13

	2


13		15




13	14



9	10
13		15



		11
			16



9		11
	14



9	10
13		16



	10
13		15



9
			16




13	14



9	10
		16



9	10	12



			12
			16



9	10	12



		11	12
			16


		7
		11	12


		7
	10		12
13			16



	10
13



			12
			16



	10		12


	7
9
		16



9			12




	14		16


		7
9			12
	14


		7

			16


	7
10
		16

	2


			16


	7
10		12
		16

	2		4

	10


	7
10
		16

			4

	10		12



9	10	12




		15	16



9	10	12
13		16

			4

	10
13		15



	10
			16



9			12
			16

		4

9	10	12


		7
9	10


		7
9


		7
9	10

backtrack.grid97 → grid98: i16 guess 13 ∈ {13|14}

pending={i16}

deduce.grid98: naked-singles

j16 is 14 by naked-single. pending={j16}

deduce.grid98: hidden-singles

deduce.grid98.col2. j2 is 13 by hidden-single.

pending={j2}

deduce.grid98: naked-singles

deduce.grid98: hidden-singles

deduce.grid98.rowj. j8 is 15 by hidden-single.

pending={j8}

deduce.grid98: naked-singles

i8 is 2 by naked-single. pending={i8}
i5 is 14 by naked-single. pending={i5}
m5 is 16 by naked-single. pending={m5}
m13 is 7 by naked-single. pending={m13}
m1 is 9 by naked-single. pending={m1}
m2 is 12 by naked-single. pending={m2}
m6 is 14 by naked-single. pending={m6}
n5 is 2 by naked-single. pending={n5}
o2 is 10 by naked-single. pending={o2}
k2 is 9 by naked-single. pending={k2}
i2 is 15 by naked-single. pending={i2}
o5 is 15 by naked-single. pending={o5}
o13 is 16 by naked-single. pending={o13}
n13 is 10 by naked-single. pending={n13}
n8 is 4 by naked-single. pending={n8}
n15 is 12 by naked-single. pending={n15}
k15 is 10 by naked-single. pending={k15}
k1 is 16 by naked-single. pending={k1}
j3 is 11 by naked-single. pending={j3}
j6 is 9 by naked-single. pending={j6}
i6 is 12 by naked-single. pending={i6}

grid98 didn't work: naked-singles ran out of candidates.

…backtrack.grid97 again

backtrack.grid97 → grid99: i16 guess 14 ∈ {13|14}

pending={i16}

deduce.grid99: naked-singles

j16 is 13 by naked-single. pending={j16}

deduce.grid99: hidden-singles

deduce.grid99.rowj. j6 is 14 by hidden-single.

pending={j6}

deduce.grid99: naked-singles

deduce.grid99: hidden-singles

deduce.grid99.rowj. j3 is 11 by hidden-single.

pending={j3}

deduce.grid99: naked-singles

deduce.grid99: hidden-singles

deduce.grid99.rowl. l6 is 11 by hidden-single.

pending={l6}

deduce.grid99: naked-singles

deduce.grid99: hidden-singles

deduce.grid99.rowl. l7 is 7 by hidden-single.

pending={l7}

deduce.grid99: naked-singles

deduce.grid99: hidden-singles

deduce.grid99.rowl. l8 is 13 by hidden-single.

pending={l8}

deduce.grid99: naked-singles

deduce.grid99: hidden-singles

deduce.grid99.rowi. i2 is 13 by hidden-single.

pending={i2}

deduce.grid99: naked-singles

deduce.grid99: hidden-singles

deduce.grid99.rowl. l15 is 10 by hidden-single.

pending={l15}

deduce.grid99: naked-singles

deduce.grid99: hidden-singles

deduce.grid99.rowm. m5 is 14 by hidden-single.

pending={m5}

deduce.grid99: naked-singles

deduce.grid99: hidden-singles

deduce.grid99.rowo. o7 is 13 by hidden-single.

pending={o7}

deduce.grid99: naked-singles

deduce.grid99: hidden-singles

deduce.grid99.col2. j2 is 15 by hidden-single.

pending={j2}

deduce.grid99: naked-singles

j8 is 10 by naked-single. pending={j8}

deduce.grid99: hidden-singles

deduce.grid99.box10. j7 is 16 by hidden-single.

pending={j7}

deduce.grid99: naked-singles

j14 is 9 by naked-single. pending={j14}
k15 is 12 by naked-single. pending={k15}
k3 is 16 by naked-single. pending={k3}
l3 is 12 by naked-single. pending={l3}
l14 is 16 by naked-single. pending={l14}
n15 is 4 by naked-single. pending={n15}
n8 is 2 by naked-single. pending={n8}
i8 is 15 by naked-single. pending={i8}
i5 is 2 by naked-single. pending={i5}
n5 is 16 by naked-single. pending={n5}
o5 is 15 by naked-single. pending={o5}
o8 is 4 by naked-single. pending={o8}
o14 is 12 by naked-single. pending={o14}
o15 is 9 by naked-single. pending={o15}
o2 is 10 by naked-single. pending={o2}
k2 is 9 by naked-single. pending={k2}
k1 is 10 by naked-single. pending={k1}
m2 is 12 by naked-single. pending={m2}
n1 is 7 by naked-single. pending={n1}
n13 is 10 by naked-single. pending={n13}
n7 is 12 by naked-single. pending={n7}
i7 is 9 by naked-single. pending={i7}
i6 is 12 by naked-single. pending={i6}
o13 is 16 by naked-single. pending={o13}
m13 is 7 by naked-single. pending={m13}
m6 is 9 by naked-single. pending={m6}
m1 is 16 by naked-single. pending={m1}
p1 is 9 by naked-single. pending={p1}
p6 is 7 by naked-single. pending={p6}
p7 is 10 by naked-single. pending={p7}

deduce.grid99. Solved.

grid99
	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16
a	12	2	13	3	5	6	15	16	1	7	10	4	8	11	14	9
b	14	6	15	16	9	2	11	12	13	8	5	3	4	7	1	10
c	5	1	9	10	7	4	8	3	14	15	11	6	12	2	13	16
d	8	11	4	7	10	13	1	14	16	2	12	9	5	15	6	3
e	15	14	8	11	12	16	4	9	5	6	3	2	13	10	7	1
f	13	16	5	12	3	15	14	7	9	10	8	1	6	4	11	2
g	4	3	10	2	13	5	6	1	7	11	15	14	9	8	16	12
h	6	7	1	9	8	10	2	11	12	13	4	16	14	5	3	15
i	1	13	7	6	2	12	9	15	10	4	16	5	11	3	8	14
j	2	15	11	4	6	14	16	10	3	12	7	8	1	9	5	13
k	10	9	16	14	4	8	3	5	11	1	2	13	15	6	12	7
l	3	5	12	8	1	11	7	13	6	14	9	15	2	16	10	4
m	16	12	6	15	14	9	5	8	4	3	1	10	7	13	2	11
n	7	8	3	5	16	1	12	2	15	9	13	11	10	14	4	6
o	11	10	14	1	15	3	13	4	2	5	6	7	16	12	9	8
p	9	4	2	13	11	7	10	6	8	16	14	12	3	1	15	5

grid99. Copying solution to raw grid.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16
a	12	2	13	3	5	6	15	16	1	7	10	4	8	11	14	9
b	14	6	15	16	9	2	11	12	13	8	5	3	4	7	1	10
c	5	1	9	10	7	4	8	3	14	15	11	6	12	2	13	16
d	8	11	4	7	10	13	1	14	16	2	12	9	5	15	6	3
e	15	14	8	11	12	16	4	9	5	6	3	2	13	10	7	1
f	13	16	5	12	3	15	14	7	9	10	8	1	6	4	11	2
g	4	3	10	2	13	5	6	1	7	11	15	14	9	8	16	12
h	6	7	1	9	8	10	2	11	12	13	4	16	14	5	3	15
i	1	13	7	6	2	12	9	15	10	4	16	5	11	3	8	14
j	2	15	11	4	6	14	16	10	3	12	7	8	1	9	5	13
k	10	9	16	14	4	8	3	5	11	1	2	13	15	6	12	7
l	3	5	12	8	1	11	7	13	6	14	9	15	2	16	10	4
m	16	12	6	15	14	9	5	8	4	3	1	10	7	13	2	11
n	7	8	3	5	16	1	12	2	15	9	13	11	10	14	4	6
o	11	10	14	1	15	3	13	4	2	5	6	7	16	12	9	8
p	9	4	2	13	11	7	10	6	8	16	14	12	3	1	15	5

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16
a	12	2	13	3	5	6	15	16	1	7	10	4	8	11	14	9
b	14	6	15	16	9	2	11	12	13	8	5	3	4	7	1	10
c	5	1	9	10	7	4	8	3	14	15	11	6	12	2	13	16
d	8	11	4	7	10	13	1	14	16	2	12	9	5	15	6	3
e	15	14	8	11	12	16	4	9	5	6	3	2	13	10	7	1
f	13	16	5	12	3	15	14	7	9	10	8	1	6	4	11	2
g	4	3	10	2	13	5	6	1	7	11	15	14	9	8	16	12
h	6	7	1	9	8	10	2	11	12	13	4	16	14	5	3	15
i	1	13	7	6	2	12	9	15	10	4	16	5	11	3	8	14
j	2	15	11	4	6	14	16	10	3	12	7	8	1	9	5	13
k	10	9	16	14	4	8	3	5	11	1	2	13	15	6	12	7
l	3	5	12	8	1	11	7	13	6	14	9	15	2	16	10	4
m	16	12	6	15	14	9	5	8	4	3	1	10	7	13	2	11
n	7	8	3	5	16	1	12	2	15	9	13	11	10	14	4	6
o	11	10	14	1	15	3	13	4	2	5	6	7	16	12	9	8
p	9	4	2	13	11	7	10	6	8	16	14	12	3	1	15	5

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16
a	12	2	13	3	5	6	15	16	1	7	10	4	8	11	14	9
b	14	6	15	16	9	2	11	12	13	8	5	3	4	7	1	10
c	5	1	9	10	7	4	8	3	14	15	11	6	12	2	13	16
d	8	11	4	7	10	13	1	14	16	2	12	9	5	15	6	3
e	15	14	8	11	12	16	4	9	5	6	3	2	13	10	7	1
f	13	16	5	12	3	15	14	7	9	10	8	1	6	4	11	2
g	4	3	10	2	13	5	6	1	7	11	15	14	9	8	16	12
h	6	7	1	9	8	10	2	11	12	13	4	16	14	5	3	15
i	1	13	7	6	2	12	9	15	10	4	16	5	11	3	8	14
j	2	15	11	4	6	14	16	10	3	12	7	8	1	9	5	13
k	10	9	16	14	4	8	3	5	11	1	2	13	15	6	12	7
l	3	5	12	8	1	11	7	13	6	14	9	15	2	16	10	4
m	16	12	6	15	14	9	5	8	4	3	1	10	7	13	2	11
n	7	8	3	5	16	1	12	2	15	9	13	11	10	14	4	6
o	11	10	14	1	15	3	13	4	2	5	6	7	16	12	9	8
p	9	4	2	13	11	7	10	6	8	16	14	12	3	1	15	5