A “C2C granny crochet” refers to a Corner-to-Corner (C2C) technique that uses the traditional granny stitch (three double crochets in the same space) to create a diagonal square.

The process involves working diagonally from one corner to the opposite, forming a square by increasing stitches until the desired width is reached, and then decreasing to form the final corner. This method results in a square that stays square, without flaring or becoming distorted.