I got the Sylvia's wedding sampler quilt book today and one of the quilts has framed each block with a very narrow band of black and then had sashing the same color as the background in the blocks. It was stunning. At the trunk show the other day, Nancy called those coping stips. It gives you a chance to get the block the right size and square...if there's been a problem. She said that the slight variation of the width of the coping stip is never noticed. It's particularly helpful when you do block exchanges and the exactness of the blocks vary. She used dark green in her's. QuiltE...that would work great with your yellow.