generative modeling for Rhino
I don't know if this is exactly what you are looking for, but there is an example of defining patterns from grids in the sample files, (http://download.rhino3d.com/Rhino/5.0/PT_GH_Samples/).
I think of the process as being Similar to custom 2d paneling operation. Except in this case, we need to define the points that make up the base pattern unit. (This is taken directly from rajaa's sample file with the minor addition of the grid point labels group)
The grid points are defined by i and j. For this pattern, after entering the highlighted i and j locations, we define a base pattern that is essentially 2 x 2.
This means we have to "shift" the unit grid by 2 in both i and j directions. (this is where I think of the 2d custom paneling operation, you need to specify the spacing for how your pattern will be distributed across the grid).
I'm still working through these myself so I apologize in advance for any potentially incorrect information!
I'm sure Rajaa will have a much more elegant description/suggestion.