This is my first ever CAD model; it's far from perfect! I noticed some of the window screens in my home were loose as a result of a missing retainer clip in the corner latch as part of the mechanism to hold the screen in place. The parts are not sold individually anywhere, and no STL model existed to my knowledge. I first attempted to make an exact replica of the original part, but I noticed that it would benefit from being a little taller at the retention point as it fit more snugly. I'm happy enough with this model as an exercise in 3D modeling and in solving a trivial home improvement problem!