I wanted to use a group of the stacked triangles that result from the first 45 degree cut on a row of fabric, stacked for octagons. While trying to decide if I should set them on white or black, it occured to me to set them on both :) By not putting them in each square, I think it gives a scattered look. I bordered two sides of each pinwheel, so they would float in the block and the "twins" could come together at the edge of the blocks.