Good idea for bathroom window.Window screens made from lace curtain fabric. By mounting the lace on a frame inside the room you can change the mood in your room by adding or removing the screen from your window.
Kitchen or anywhere DIY. Seems simple enough, depending on your gap between shelves, anywhere from ropes to ropes for your spacing. You could even use wider wood, just adjust your rope length to accommodate your width and height of your shelves.