I'm sure there's a clean way to do this, but I'm probably not using the right keywords for find it.

So let's say I have a grid. Starting from a position on the grid, return all of the grid coordinates that fall within a given distance. So I call something like:

getCoordinates( currentPosition, distance )

And for each coordinate, starting from the initial position, add all cardinal directions, and then add the spaces around those and so forth until the distance is reached. I imagine that on a grid this would look like a diamond.