You will need to use a circular needle for this pattern (or a really long double point). Flat 2 color brioche requires that you knit across the first dark color row and then slide the work back to where you started to work the first light color row. Once that is complete, the work is turned. This sliding action cannot be accomplished on traditional straight needles.
The pattern is free and can be downloaded at Double Brioche Scarf
Photos copyright Prairie Willow Knits.