Are you asking about a certain DIY you have seen before? We need a little more info so we might understand the project. Thanks
Here's some ideas for re-purposing sheets from other Hometalkers that might inspire you Dei
I have made curtains or shower curtains with sheets.
Here are some cool projects for vintage sheets, but you could use new ones as well: https://www.polkadotchair.com/cute-vintage-sheet-projects/