The eyelet ruffle of death:
rnd 1 - k2tog yo to end of rnd
rnd 2 - k to end of rnd
rnd 3 - k1f&b in every stitch to end of rnd
k rnds 4 & 5
repeat rounds 2 through 5 until you have the ruffle you desire (that sounds like it’s from a bad romance novel;)

I ended the body of the blanket with 50 stitches in each of the 10 sections = 500 stitches
After the first ruffle repeat I had 1000 stitches!
After the second, I had 2000 stitches and no more yarn. I had planned on doing another repeat on the ruffle, because 5 balls of yarn should be enough for the ruffle when the body only took 8, right? Wrong! Just as well though, because 2000 took quite long enough to cast off, thank you.