I just finished an afghan to donate. The 6 inch squares are from "101 Crochet Squares" by Jean Leinhauser; published by American School of Needlework. I used a G hook for those. The plain squares are just granny squares. I used an H hook for those. Start with 4 chains. 2 chains at the corners and 1 chain in between the sets of double stitches on the sides. Keep going until you have 6 or 12 inches. I joined four 6-inch squares to make 12-inch squares. Then I joined the 12-inch squares with the lattice desing like on the Crochet Dude's Monet afghan.