Meet me At the Corner

Here is another work in process/progress...It is made out of Fossil Fern fabrics, and is a streak of lightning setting idea and block design I got out of Quilter's Newsletter Magazine ages ago. I got it this far and then ran out of steam on the corners.

I'm seeing several possibilities looking at it again with "fresh eyes"(ie;starved for fabrics!)... One is having a plain matching white background square in two corners diagonally opposite each other, and in the remaining two corners some sort of spiky star-ish kinda thingy...
Any ideas out there for me?