A scalloped edge is created by using a shell stitch (putting a half-circle amount of stitches into a single stitch) to create a more frilly edging. Into the corners of your blanket, you will work 9 stitches to take it around the 270° angle.
STEP 1 Do a round of double crochet (follow the previous instructions).
STEP 2 Join into a stitch 2 away from a corner, then work 9 stitches into the corner-space.
STEP 3 Skip to the 2nd stitch after the corner-space, and join with a slip stitch.
STEP 4 Skip another stitch and work 6 treble crochets into the same stitch, skipping another double crochet to then slip stitch into the next one. Continue like this to the end.