I have a disappointing lack of yellow in my stash. I didn't realise it till tonight, when I needed some. I found two nice yellows, that worked okay in my bundle, but I only had a fat quarter of one, and 30cm of the other. I chopped and changed my bundles, trying to make it work with one of the brighter yellows that I had enough of, but they all looked weird. I needed a dusky yellow, that wasn't too lemon-y. And I needed to be able to get sixteen 10cm squares and eight 15x17cm rectangles from it.
Eventually I found two matching straggly bits in my corner pile of random bits, and - Yay. It took a diagram for me to work it out, but you can get the bits I need from a 50cm square and a slightly-more-than-15cm strip. Hurrah for the quiltmaths :)