Baby Surprise Jacket

I joined a knitalong to make Elizabeth Zimmerman's famous Baby Surprise Jacket.  A jacket like any other, nothing special, except that it is knitted in one piece (almost, only 1 seam) So how do you knit in different directions at once? I was curious so I purchased the yarn and started knitting. I had no idea what I was doing and even after casting off I was not sure this was going to be a jacket.

But then you fold it this way and that way and tadaaaa: