Spike stitch: single crochet placed 2 or more rows below your working row and drawn up to the height of a standard sc. A would be a spike stitch worked 2 rows below, and a would be one worked into the row down from your working row.
The Loopy Love Blanket is so fun to make! The pattern is easy to memorize, the stitches just fly by, and the end result looks way more complicated than it should. And in 3 colors, you can change colors every row and never have to cut the yarn!