src/main/java/org/teachingextensions/logo/utils/PuzzleUtils/Puzzle.java
public Puzzle swapBlank(int target)
  {
    int[] copy = Arrays.copyOf(cells, cells.length);
    int x = copy[target];
    copy[getBlankIndex()] = x;
    copy[target] = 8;
    return new Puzzle(copy);
  }
public Puzzle swapBlank(int target)
  {
    int[] copy = Arrays.copyOf(cells, cells.length);
    int x = copy[target];
    copy[getBlankIndex()] = x;
    copy[target] = 8;
    return new Puzzle(copy);
  }
Create a copy of the puzzle where the blank swapped with the value in the target position

@param target
move the blank to this location, and move the value from this location to the current blank location
@return A copy of the puzzle with the blank and target swapped.