This is an example of a starting grid - none of the grid is filled in initially.
The easiest place to start is to look at those clues that can only be satisfied one way. This will
typically include these types of clues,
- '0' clues - we know that none of the surrounding cells connect to these nodes.
- '4' clues - we know that all of the surrounding cells connect to these nodes.
- '2' clues on a side - these are similar to '4' clues, we know that both surrounding cells must
connect to these nodes.
- '1' clues in a corner - we know that the only connected cell here must be connected to this clue.