It’s done!  The shell stitch scarf.  Unfortunately I have photographed it draped around the bannister rather than draped around the neck of a person – sorry about that!

I really love the texture, both of the shells and the ridges that have evolved lengthways.  Here’s a close-up of the shell stitch:

Many thanks to bella dia for the inspiration!  It worked up quickly and I found it very satisfying to make something that I sort-of made up myself.  In the end it took five balls of yarn – yikes!  Mum thinks that it could have been narrower – maybe the next one I make won’t be as wide, but I think that the width works for this scarf.