Here's one I made for my nephew. It measures 38" or so, but can be really any size you want. It's great for fabric you don't want to cut up! I LOVE the corner stars, I made them wonky on this one and used several shades of yellow. Re the border colors, the inner border was supposed to be one color and the outer border a second color. My DH suggested changing them up, but that left the very outer corner with no clear identity. As I'd already sewn it at that point, I didn't want to reverse sew it, so I put in the blue fabric.
At the binding I added the flat welt (flange) and deliberately made it wonky too, but in places it looks like I just didn't know how to sew a staight line...if I do that technique again, I'll use a wider strip for the flange and really do it up right! :?