Working from right to left, use one thread, known as the couching or
working thread, to tack down one or more laid threads, known as the
couched threads. Bring the working thread up at 1 and insert at 2, over
the laid threads to tack them down, bringing the needle back up at 3.
The laid threads are now encircled by the couching thread. Repeat to
couch the desired length of thread(s). This stitch may also be worked
from left to right, and the spacing between the couching threads may
vary for different design effects.