In this Nurikabe puzzle, each clue is off by one; however, the clues are right on average. That is, two clues are one smaller than they need to be and two are one larger.
[Solution on page 2]
Here is a pair of Nurikabe puzzles.
Here is one Matryoshka Nurikabe puzzle. The complete grid solves as a regular 10 by 10 Nurikabe; peeling off the outer frame reveals a new 8 by 8 Nurikabe; peeling off the outer frame of that yields yet another 6 by 6 Nurikabe – and so on, all the way down to a 2 by 2 puzzle in the very center.