Marking a Grid Member Via Code

Hi there,
I am setting up a grid of tiles at run time, 10x10 for example.

What I am wondering is, I want to mark some of these tiles and am struggling on how to do so via code. So, for instance, I want tile 3,3, 2,2, 1,5 and 3,9 to be marked.

How would you do this? I am thinking an array, but I cant quite sort it.


Thanks