I made this blanket for my son last year, and brought it out for the first time this year today. It was very easy to make and turned out huge!
I couldn't get a photo capturing the size because my son kept walking on it, so I may try again tomorrow, but I wanted to get out the description of how I made it sooner.
Proof of a munchkin walking all over mommy's photo:
I ended up making it a rectangle size - about five feet long and two feet wide. I like this because I could put it underneath my son's tush in the stroller and then still bring it up to his chin. I don't remember the type of yarn I used, but you can see that it is pretty thick.
Anyway, the pattern - I cast on about 80 stitches and knit the first ten rows.
Row 11 and all odd rows - knit ten, purl until the last ten, knit last ten
Row 12 and all even rows - knit
The last ten rows should be knitted, as well
Thanks for reading!