We still have a black grid here, but now the lines are gray and there are white circles in the intersections. Have a look and try to count all of the black dots you see.
Step 1: What black dots?
The goal of this Instructable is to show you how to quickly recreate such a grid with a graphics program. You can then make some variations of your own.
To start with we'll want a gray background. Lock this or put it on another layer and then start making your building block.
Step 2: Building block, pt. 1
To start, make a black square and make two identical smaller squares of another color. Attach these squares to the right and bottom of the black square.
These smaller squares will determine how wide the lines between the black squares are and are a guide for all the copying we'll be doing.
Now group the squares and let's go.
Step 3: Copy and paste
Now select all of the squares, copy them, and paste them directly below the first group. Use the little squares as a guide again to keep the distance consistent.
The results should look like the image below.