Cast on 240 stitches (80cm needle, approx 86” of yarn for the long-tail cast-on).
5 rounds of garter stitch at the beginning and end.
21 pattern repeats.
Cast off: k2togtbl, pass the resulting stitch to left needle, repeat to the end.
Size after blocking: 6” x 46”.
Delighted!

(The true colour is much darker than would appear from the pictures - a real blue/black ink shade.)