I just finished the Never Ending Granny Square Afghan that I started several months ago.
You can see that the center starts with green and then sort of spirals.
I wasn't quite sure how to end the afghan. I looked at different sites on line and finally decided to do mine like this. Here is a photo, but I didn't want to end with white.
I had enough black yarn to go one more round, and this is how I ended. The first ending row has 3 double crochets (green) in the "hole" from the row below. The next row (white row) has one double crochet The end row (black) has 3 double crochets.
You can read more about this afghan in my post here.
I did this afghan as a Crochet Along with Cyn from Cyns Quilted Travels blog and Pat from Pat's Patter. You can click either link and see their afghans in progress. You will also see that all of their skeins are attached to the afghan at once. I used Cyn's method for making the afghan with no tangles, but I still spent a fair amount of time untangling my yarn. So now that this is finished, I'll probably stick to afghans using one skein at a time, but I'm glad to have quilted along with friends on this one.