This pattern is also known as “Striped Scarf” in Men’s Knits: 20 New Classics.

From the Book:
The simplest of scarves in the softest of yarns. Worked in garter stitch, this wool scarf is comprised of bands of luxurious baby alpaca yarn. Each stripe is worked in long rows, from end to end, on a circular needle, so the edges of the scarf lie flat and do not curl.

Yarn Requirements:
3 balls of Rowan Classic Baby Alpaca DK in each of color A, B, and C.