I really like the randomness of the arrangement with the mix of colors. But I'm going to be a little different from the others that posted and throw out the possibility of very narrow black sashing, but not between every block. Maybe four blocks sewn together, set on point with black sashing (about 1 in. finished width) and colored cornerstones of some scraps of the fabrics used on the blocks. But there is nothing wrong with just sewing it together as you have it layed out.