Text at top reads “target is 6”.

Diagram 1. An arrow points from a box labeled “head” at left to a two-tiered box at right, which is at the top of a column of four two-tiered boxes. The top tiers of these boxes contain the numbers 2, 1, 6, and 3, respectively. Arrows point from each of the bottom tiers down to the next box in the column, except in the bottom box, which contains the text “NULL” in the bottom tier. A box labeled “here” below the “head” box contains a question mark.

Diagram 2. Same as Diagram 1, except the “here” box has no question mark and now points to the top two-tiered box, and the “2” in this box is labeled “Not here”.

Diagram 3. Same as Diagram 2, except the “here” box now points to the second two-tiered box instead of the first, and the “1” in this box, instead of the “2” in the top box, is labeled “Not here”.

Diagram 4. Same as Diagram 3, except the “here” box has moved down and now points to the third two-tiered box, the “6” in this box is labeled “Found”, and the “1” in the second two-tiered box is unlabeled.