Couching around a right-angle
This method gives instructions to achieve a nice crisp 90° angle when couching gold, silver or copper metal threads.
For more background see the entry for Couching.
Method
1
Secure by couching a pair of metal threads at equal intervals. At the corner turn the metal threads 90° and work a diagonal stitch separately over each thread.
2
Continue to couch over the metal thread in pairs by couching at equal intervals.
3
Take care to achieve crisp 90°corners, by couching over single threads diagonally at the corners, but try to avoid exposing the thread core.

Structure of stitch
References
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Various Authors, The Royal School of Needlework Book of Embroidery (2018)