How to do Patterns in Geometry Nodes?

Hi anyone has a clue of how one might do a typical pattern design with GeoNodes?

I managed to do it using line segments, with using one as the base and another for the height, turn each of those to points and instance a collection of images with some icon svg texture.
All fine but then I would need ever 2nd column to be offset in Z by some amount and every 2nd row to be offset in X (for example) and I can’t figure that one out.

I did try to capture the index of the points and modulo that with 2…but that appears to have worked only for the rows but not columns…

Any suggestions are welcomed.
I tried doing the pattern in krita, but that was an overkill for my machine using clone layers. A simple 10x10 grid takes like 2min to update. Blender does it super fast but I can’t make it to work as I wanted.