What is the process for generating 2D arrays that are shifted by a certain number of rows or columns?

I came across this piece of code with the heading “Creating ‘n’ shifted 2D Arrays”, pasting the code below:

though the function works fine and yields a result, the function itself doesn’t have comments in it to understand the concept of this term accurately. Can anyone please explain the functionality of the code or provide a simpler function similar to this with a brief explanation?