Not long after moving into my house, I noticed that the window blinds on some windows were too narrow. As a result, if you pulled the pull string in the wrong direction, the blinds would slide and fall out of the bracket holding them to the window sill.

So I broke out the calipers and modeled this spacer that sits between the edge of the head for the blinds and the inside of the mounting bracket. I've attached the 3MF so that the spacer and bracket for the inside of the blinds can be tweaked for other installations.