I then worked the black around the corner, making the combination of 3dc cluster, ch2, 3dc cluster in the top of the last dc in the round below (purple). The next 3dc cluster was worked in the side of the next round (blue/grey) and from then around as normal. You are very aware at this point that this corner is not like all the others, but once you step away from it for a while, you'll forget all about it.
I had originally planned to end the blanket there, but then this morning I was watching Knitting Daily on PBS, and saw an idea for an edging that I thought would work perfectly for this blanket, especially if worked in a multi-color yarn. I did break out a brand new skein for this, but it could be done in scraps as well if you wanted. I didn't want to have to fuss with burying yarn tails at this point, so having enough yarn to go all the way around the blanket was important.
I started with making a ch1 and a sc, then a ch 3 in the black in the ch2 space of the corner. I dropped the black yarn. Then in the next stitch I tied on the color, worked a sc in the top of that same stitch, then a sc in the next stitch and a ch 3. Then I dropped the color yarn and picked up the black again. The ch 3 in the color and that yarn are held in front of the working row, as you can see in the photo. With the black work a sc in each of the next 2 sts (doesn't matter if it's the top of a dc or a ch1 space), ch 3 and drop the black. Pick up the color, hold the black ch 3 and the yarn in front, and work a sc in each of the next 2 sts, then a ch3. Repeat and repeat and repeat. You will notice that the yarns end up all twisted around each other and you will have to stop and untwist them; yes, it's annoying, but the result is worth the extra effort, I think.