Elizabeth Zimmerman, the matriarch of modern knitting, would have designed it =) =) =)
Starting at the top, notice the yoke style neckline that is perfectly sized for Joseph's proportions. It's knit back in forth in random colored strips rather then in the round. Abigail must be as scared of steeking as her mommy!
The sleeves however are knit in the round and the random strips are continued. Both the neckline and cuffs don't appear to roll, so I'm guessing they were knit in garter stitch, EZ's all-time favorite.
Now onto the body of the coat. Instead of more random vertical strips, she decides to do an extra, extra, extra long knitted-on border to form the body of the coat. This is where Abigail truly shows she is not a blind follower and does a bit of "uninventing". Elizabeth would be so proud of her!
If you are a knitter and haven't heard of Elizabeth Zimmerman, I encourage you to check out any of her books at your local library. Her book titles:
Knitting Without Tears
Knitter's Almanac (my personal favorite)