By making an extra stitch in Herringbone smocking, you can
add an outline to the border.
Start on the left side of the first pleat, and stitch through
the first two pleats (Step 1). Travel down to the next row,
and stitch through pleats #3 and #2 (Step 2).
Step 1:
Step 2:
Finished Stitch:
An interesting variation of this stitch
involves working the border in two passes, in contrasting
colors. Each traveling stitch covers 4 pleats instead of 3.