For every crafter who has ever wondered how to use the odd ball of yarn left over from a previous project, the answer is here. Now that more and more of us are buying online, there's always a temptation to add one more ball to your basket than the pattern recommends, just in case you can't get the same dye-lot at a later date. Or maybe you are one of the lucky ones who always seems to use slightly less yarn than you expected. And then...