A friend asked for a crocheted headband to keep her ears warm. I sat down to make my prototype and got it right on the first try.
I started with a row of chains twice as wide as I wanted the finished headband. Then I used a *single crochet, chain* stitch. The next row you make the single crochet stitches in the chain spaces. This creates a fluffy and stretchy fabric. I made enough rows that the strip fit around my head. I folded the strip so that the right and left edges were together and single crocheted the edge closed. Then I hand-sewed the seam to make it a circle.
Amazingly it was exactly right! I was able to finish the whole project in about an hour. And my friend loves the headband. Since it's double-thick, it's super warm.