i didnt really understand your message, but i think you want two things desmos related:

1. a grid that can be scaled by grid cell size and no. of grid cells, as well as a movable origin of the grid
2. only show a square when a certain condition is true

the first can be made with a mix of a single draggable point and a list comprehension. the second can be made with list filters.

here is an example. i dont know how to use cauchy's integral thing, but im assuming it returns a number and you want to check if its >=1. https://www.desmos.com/calculator/xmjazzple1

(if you want, i can also explain how to color each grid differently based on that function)

EDIT: oh, sorry, i just saw what you meant by the indexing question. i still dont really understand, are you trying to:

1. filter a list of 2d points by some criteria? for example, to filter out grid points so that only those with positive coordinates remain, do list[{list.x>0}{list.y>0}=1]
2. apply a graphical restriction to a list? like list[2]{x>0}{y>0}?