Use the Tunisian “knit” stitch. A good tutorial can be found here. Row 1: ch 15 for a narrow scarf, or 42 for wider ... Repeat row 2 Repeat row 3 & 4 for pattern. When changing color ...
Continue knitting in the round with MC for 20 rows. Repeat from * to ** until the scarf is the desired length. Knit 20 rows in MC. Bind off, weave in ends and sew the ends of the scarf closed.