Fourth Knitting Project: This Hat is Too Small!

Remember that Gnomey Hat I made for my midwife's little one? On our trip to the yarn store, Big B picked out a skein of that same self-striping yarn in a cool blue palette. I got to work on a hat for him, following this pattern, shortly after the Gnomey was finished.

The dark side: I realized late last night that something had gone awry. I finished it anyway, and it doesn't even come close to fitting Big B's head. Was it my needles? The yarn? I suppose a good lesson is to measure the circumference of the head upon which you'd like the hat to sit.

The bright side: Without my suggestion, Big B immediately offered the too-small snuggly to his little brother, who was reaching curiously for it. Papa helped little b put it on. It fits, barely and tightly. This knit just might have to find its way on a plane to Sweden...
I still owe Big B a hat. If any knitters reading this have a great relatively easy pattern to share, I'd be very grateful!