Nina, welcome to the board. As you can see, it's not very active.
I saw your post and although I'm not interested in trading patterns, I would like to post a resource for you to find granny squares.
Some of the links on this Pinterest board lead to more collections of granny squares, and if you do a search on the subject on Pinterest, you should get a feed of thousands of them, all with pictures.

Here is a link that might be useful: The Granny Square Directory

Alas, I do not know how to crochet, so I have never saved any patterns for Granny Squares. I'm sure you'd be able to find some on Ravelry, though.

I can remember that my paternal grandmother had made a Granny Squares afghan when I was a child. I loved that thing!

Please post photos of anything you make, because we'd love to see them. :-)