I'm trying to show a two-dimensional array in the editor like the "Layer Collision Matrix" is shown in Unity:
![enter image description here](https://i.stack.imgur.com/YjFJh.png)

Though instead of checkboxes I need ints, and a full grid (not the triangle shape.) I can't seem to figure out how to do this though... I can get a custom editor, though making the grid fails. So, is there any way I can see the code of the Physics Manager's editor (the Layer Collision Matrix is in there) or maybe someone knows a good way to do this?

Note: Preferred language is c#, though any will do.

Thanks.