I am not the best crocheter, but I put all my heart in my crocheted squares for Shelly's project, and it was lots of fun trying new patterns and stitches for those 6 inches squares! 
I have picked happy bright colors, keeping in mind that black yarn is going to link all squares together, and that those afghans are going to be for children.
Patterns: Zipper Square - I love it! 
Jackie's Heart Granny Square
Diana's Flower
Small Square
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Also, I thought that the 4 Corner Dishcloth would be an original addition to an afghan made out of squares, and it would look great made with my favorite colorway of varigated yarn, Polo (Red Heart) - unfortunately discontinued...
I have made the dischloth only once - and it was six months ago, but I was pleased and amazed to see today that the pattern was still in my memory...
I guess some projects are just unforgettable... 
For those who are interested, I cast on 14 stitches for making the 6 inch square with needles #8US. Gauge: 10 stitches x 20 rows = 2 inches
