Night was the problem, as soon as it got dark enough to need the lights on in the living room it was time to stop crocheting. The black acrylic yarn I was using was impossible to see properly in artificial light as it has not natural sheen.
Anyway, I finished sewing the squares together on Sunday, then on Monday I did double crochet all around the edges to neaten them, and she has her scarf ...
But that isn't the end of the granny squares. now i'm making slightly bigger squares for a bed cover. The colour scheme is totally different as you can see.
The yarn is Sirdar Calico,a soft cotton acrylic blend that is a dream to crochet with. I'm not sure how big my cover will be, nor how long it will take, but it's relaxing to do, and at least I can see the stitiches i'm working into!