These rows start with 1 tr, have 66 tr groups, then end with 1 tr. The edges of your blanket may look a weeny bit wobbly, but once you've darned in your ends and worked a border around at the end, I ...

They take concentration folks, but if you are prepared to concentrate then these will reward you handsomely. I'm not sure how this post will turn out, maybe a bit of a descriptive pattern/tutorial ...