3 ideas jump out at me. All include finishing the left side 'circle' and doing a white floating border. #1 is to add another 'circle' for width and length before floating border and a white binding. The second would be to add additional borders either a braid using all the colors and then another white thin border or a piano border within the 2 white narrow borders. The last is more traditional. I would use a white floating border and then 2 borders of the same width- inner would be the same as your center squares and the outer would be your favorite color from the block. Any darker color would work, a blue, green or brown would frame it out perfectly. I do not think it would be boring at all. Please post the finished product for us. I am excited to see what you choose to do.