Island expansion from a clue

The 'Island expansion from a clue' technique is a fundamental technique suitable for beginners. This technique revolves around expanding an island based on the initial clues provided.

Start with a clue that indicates the number of connected cells that should form an island. The clue dictates how the island should be extended. For example, if there is a '4' in a cell, that means the island must extend to have four connected cells.

The expansion should be done in a way that it does not touch any other island, while also ensuring that it does not create a 2x2 block of wall cells. Each move should be logical and within the rules of the game.

Remember that once you've defined an island completely, you can then start to mark the surrounding cells as walls, as no two islands can be adjacent. Also, these wall cells cannot create a closed-off area or a 2x2 block.

Here's an example of the Island expansion from a clue technique in action: