I used Paton's chunky yarn, but any chunky will do.
Gauge doesn't matter (it's a scarf)
Cast on 80 stitches with size 6mm. needles.
Work 6 rows in garter stitch.
Change to pattern
Row 1: K1, *yo, K2 tog., repeat from * to last stitch, K1
Row 2: Knit
Row 3: K2, *yo, K.2 tog, repeat from * until 2 st. remain, K.2
Row 4: Knit
Continue these four rows until scarf is within 1 inch of the desired length. Knit 6 rows garter stitch. Cast off.
If you want, add a fringe to each end.