A granny square is a small, flat crochet motif worked outward from the center in rounds, usually in clusters of double crochet separated by chain spaces. Squares are joined together to build blankets, cardigans, bags, and more.
The classic granny square is one of the most recognizable crochet motifs — endlessly variable in color and easy to make in portable batches, then seamed or joined-as-you-go into a finished piece. It's a favorite for using up leftover yarn from your stash.