Crazy Mom Quilts. She spells it out in her book Sunday Morning Quilts, which I happen to have and adore. This is so easy, though, I think I can just tell you how to do it right here.
You start by layering and spray basting the backing, batting, and white face fabric together. Then you just grab all your littlest squares and rectangles in your choice of colors from your scrap bin. I went with red, yellow and gold, plus green. You stitch these down, one at a time, through all the layers. It's almost like putting a puzzle together. Just find a piece that fits the next space, and don't worry whether it looks perfect or not. When you finish sewing on the last little scrap, your quilting is done as well!
I admit that the wonkiness of it adds to the charm. However, the raw edges are a stretch for me. Being an old-school seamstress (emphasis there on old), I like to finish all my edges to prevent raveling. These little pieces are going to fray just a bit and I know it. It's allowed. I'm dealing with it.
Every time I look at it, I like it more. It reminds me of a little stained glass window. And it was essentially free, which just makes me exceedingly happy.