Need a Little Help Please

Here are 2 pictures of the quilt I am working on for my "Scrap Bags" Log Cabin challenge. Originally the black squares were going to be violet and the logs were going to be blues and pinks. Then I remembered, when I issued the challenge it was to have 4 or more colors.
So now I have a truly scrappy Log Cabin.
Ok, so the problem is I don't know what to use for the side and corner triangles. I'm thinking a black and white print I haven't used in the body so far. I don't think I want to use solid black. What would you do? Please help! Leave a comment! My deadline is April 30th.