For the 2013 Rainbow Challenge, I made 18 of these 16" blocks. I pulled a Train Fabric from the stash and 9 of the blocks for this "boyish" quilt --- designated for a very special young boy due any day. The hardest design was the cornerstones, which I auditioned several colors. I ended up using a light print left over from one of the blocks.
The remaining blocks are very "girlish", so I will dig through the stash later and starting testing. For other Rainbow Challenges, visit Angela at her SoScrappy Saturday check in. Although we are in the last weekend, I am pushing to finish the above top and so I can put the last one on the design wall this afternoon!