Looks like a multiple of 3 stitches (18 stitches in that pic) doing short rows increasing by 3 stitches knit on each right-side row.
IOW, K3, turn, K3
K6, turn, K6
K9, turn, K9
etc until all the stitches have been used up. Knit one row (to get to the opposite side of the scarf to alternate wedges) Then start all over again.
This is my best guess but would swatch to make sure.