Adjacency

==Tile Adjacency.==
Adjacency is when a tile touches another tile. There are two kinds of adjacency on square tile maps. There is "normal" adjacency which is just called ADJACENT, and then there is cardinal adjacency, referred to as CARDINALLY ADJACENT.
==Adjacency==
Adjacent tiles are any of the 8 tiles that touch the tile in question. Adjacent tiles may also be referred to as 8-adjacent. In the image below:
*The blue tile is the tile in question.
*The green tiles are adjacent.
*White tiles are non-adjacent.
==Cardinal Adjacency==
Cardinally Adjacent tiles are the 4 tiles that directly touch the tile in question, not including the corners. Cardinal Adjacency gets its name from the "four cardinal directions" of North, South, East, and West. In the image below:
*The blue tile is the tile in question.
*The green tiles are cardinally adjacent.
*White tiles are not cardinally-adjacent.
== Diagonal Adjacency ==
Diagonally adjacent tiles touch a given tile diagonally. This is just an easier way to say "adjacent tiles which don't qualify as cardinally adjacent." 
In the image below:
*The blue tile is the tile in question.
*The green tiles are diagonally adjacent.
*White tiles are not diagonally adjacent.
== Hex Adjacency ==
On hexagonal maps, the geometry doesn't differentiate between adjacency and cardinal adjacency. There is only one kind of adjacency. Therefore, on hex maps, rules for adjacency and cardinal adjacency are treated the same. That is, adjacency and cardinal adjacency are synonymous and any rule for one or the other is treated the same, when playing on a hex map. In the image below:
* The blue tile is the tile in question.
* The green tiles are adjacent, and will qualify as cardinally adjacent also.
* The white tiles are non-adjacent, and will not qualify as cardinally adjacent either.