Even with dark curtains, when the sun shines into my window in the morning, it sears my retinas, stabbing my poor little brain into migraine mode and spoiling my whole day. I can't afford to order blackout curtains or get blinds fitted (and anyway, they'd take up too much space, stopping me from using my window sill as a storage area). And I do want to be able to open the window for air, or look at the view when it's not too bright outside, so don't want to fill up the whole sill with storage.
Something lightweight that lets very little light through, which I can put up and take down every day (or as needed). Cardboard is like that, and I happen to have a lot, as I get most of my footwear in RocketDog sales. (I won't bother with a link - somehow I don't think they'll want to use this blog post in their marketing material.) Oh, and I like boots, so just happen to have a couple of big cardboard boxes lying around. Only thing is, if you put a big sheet of cardboard up, it'll just fall over. You need it to have an unbendy structure. This is where I had the idea of taping boxes together and lids together, to make up large areas of cardboard, that can either balance on their own (as you can see with the boxes), or just prop up somewhere.
Here's where I get really proud of myself. I know from experience that gaffer tape is really heavy and won't do for this purpose. But if I use masking tape, not only will it hold the cardboard box components together, but if I need to use them in the future as boxes again, I'll be able to take the tape off without tearing the boxes apart!
Now all I need is to have the same brainwave to solve my boot and shoe storage difficulties - a project I've been wrestling with for a couple of years...