C# Calculating Slots hit with AOE in a 4x3 Array : I'm not exactly what terminology to even use to look this up, and I figure the best way to explain it is with an example image.

I have a game field made up of 12 (numbered 1-12) slots, 4 wide and 3 deep, I need to be able to take the main slot number hit and get the numbers of it's neighboring slots for an Area of Effect system.

I'm using c#

[Example Image: AoE on 4x3 array of Slots][1]


  [1]: https://i.stack.imgur.com/O02Ae.png

Any help is appreciated.