I want to make a mattress extender, but to make it wider instead of longer. There’s about 20-25 cm between my bed and the wall, I’ve got square buckets of hydroponic media there for storage but I think it would be nice if I put some sort of mattress extender on top of it. Perhaps I can just make it out of an old duvet cover, which is already the right length. I’ve still got a bag of foam scraps that I used to make my beanbag, I don’t know if it’d be enough.