There's an aqua & green mottle that I'm liking. It's in the outer sawtooth points of the top row middle block and also in the inner star of the far right block in the second row. I would make alternate blocks of simple irish chain with this mottle for the background fabric and a dark for the chain squares. The black would be preferred but if there's hardly any left maybe just the center square of the chain blocks. Then I'd use a straight set so the chain blocks create the illusion of the quilt being set on point. I don't think a repeated alternate block would detract from the BOM blocks if done right. Same idea as eparys' quilt only with a twist. That's a well done quilt BTW.