Back story from the pattern text:

When I was learning to knit socks, the heel flap was my favorite part. I was always disappointed when I reached the end — far too quickly — and had to start working the gussets. This scarf solves the heel flap lover’s dilemma: It provides hours of heel flap happiness with no gussets in sight.

Scarf description from pattern text:

This is a traditional long rectangular scarf, knit flat in heel flap stitch with stripes of linen stitch near the ends. It needs blocking to reduce the curling tendency of the heel flap stitch, but it makes an attractive, textured, cozy fabric and produces a classic scarf that adapts to many yarns, gauges and sizes.

Yarn and knitting needle notes:

While the sample knit for the pattern is knit in worsted weight yarn, you can use any yarn and knitting needle size that produce a fabric you enjoy. One caveat: A protein fiber is strongly suggested, as heel flap stitch curls, much like stockinette stitch. You can block out some of the curl if you use a protein fiber like wool or alpaca, but I can’t vouch for the good behavior of any Heel Flap Scarves knit with something like linen or cotton. ;) If you find that your scarf curls too much, try using larger needles for a slightly looser fabric.