BLACK DOG ON MY SHOULDER

Black dog on my shoulder, is that the right expression? I have not really a dog on my shoulder that would be silly or even funny but I still have those meloncholy feelings. Or does that mean I fancy a piece of fruit?

I am knitting a pair of shoes for a bear, green with pink soles and a pink bar across the top. Whilst I am knitting the black dog goes for a walk. Unfortunately I cannot knit for 24 hours a day.

Yours knittingly

Celia