I contacted Cathy (thanks Cathy!) and asked about her blocks, then went digging through the scrap bins. It just so happened I had a huge assortment of already cut 3.5 inch strips in lots of colors and shades. So by default, my Greek Square blocks were made from 3.5 inch strips and squares. I pieced 4 green squares and 2 red squares; I've got two more red squares ready to piece during the week.
Mine are a little different from Cathy's in that I used light/dark fabric combinations and she used white for her light fabric. Since I already had the light/dark fabric strips cut, I decided to use those rather than cut even more fabric!
As I was working on the scrappy rainbow blocks, I realized I could also use this block pattern for one of my memory quilts. I already had a big stash of half-square triangles and pieced light/dark squares. I made a quick block on the design wall and was pleased with the result. Now I only need to make a couple hundred more half-square triangles for the various memory quilts under construction!
There's lots more inspiration over at the 2012 Rainbow Scrap Challenge link up for this week - take a look and see if you don't get inspired!