I chained 220 with a 7mm hook (I always, always use a hook two sizes up for a foundation chain when I'm making a scarf - it stops that annoying curve) and then, using a 6mm hook, simply worked half trebles (half doubles US) in the back loops.
Make it ! The Granny Yarn Chain !!!
Make this crochet granny yarn chain - for a cute unique scarf or decorative garland