Separate Completed Blocks

In a black-and-white Nonogram, a completed block must have an empty cell immediately before and after it unless it touches the edge of the grid.

Clue:

3

Known block:

· · ■ ■ ■ · ·

After completing the block:

· × ■ ■ ■ × ·

These empty cells prevent the block from becoming longer than the clue allows.