• you tuck the edging into a 45 deg angle. You basically stitch to right at the end of the straight, lift the needle, turn the fabric and binding, then tuck the corner into a neat 45 deg fold before putting the needle back in, but you have to do it without pulling the threads to far.
    Basically you don't just let it form a lumpy old mess on the corners. :)
    Practise edging on scrap fabric till you suss corners.

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