This jacket was a favorite at my shop. You use 6 colors of sock yarn, 2 strands at a time, and change one strand every 6 to 8 rows, depending on size. You can use solid colors, hand-dyed colors, or self-striping or a combination. If you are using the typical 100-gram ball yarn of sock yarn, you will need 6 colors, and 2 balls of each color no matter which size you are making. The smallest size barely gets into the second ball of each color, and the largest size uses most of the second ball of each color. The jacket is worked side-ways to attain the slimming vertical stripes. To set off the colors, the knitting is done in a 3x3 travelling rib.