That's fine, all you need to do is change the event for spawning the filler object to the destruction of the object you are counting. You will want a variable to store the number of items spawned. Then, calculate the X and Y values from the number of items spawned, not the position of the click. My example should show you everything else you need.
If the problem you are having is trying to figure out how to get the correct position of the object, you could use the following:
X:
((NumberSpawned % 4) * Filler.Width) + Background.X - (Background.Width / 2) + (Filler.Width / 2)
Y:
((floor(NumberSpawned / 4)) * Filler.Height) + Background.Y - (Background.Height / 2) + (Filler.Height / 2)
In the above, the 4 represents the number of positions vertically or horizontally you want to fill. In your original question, you said you wanted a 4X4 fill area.
As I stated in my first post, the question you asked did not explain enough about what you wanted to know. To get good answers in the forum, you need to be able to ask good, clear, descriptive questions. That way, those of us willing to help will know exactly what it is you need help doing.
Once again, good luck with your project.