This is a vent diverter I made because the left side of the vent in my bathroom is aimed directly at the front of the shower, over the shower door.... I don't know how anyone thought that was a good idea, but I wanted a non-permanent fix to the problem, so I made one. This design is meant to just cover one side of a vent.

I used two rectangular magnets to hold it to the vent and some thin foam to keep where the part meets the vent air tight.

I printed it on my ender 3 pro at 0.12mm layer height in white PLA, but do whatever works for your printer. I used Cura as the slicer with the experimental tree supports, and they worked like a charm (I love tree supports).

I was inspired to design and print a fix for this by the F*** This I'll Just Print It Facebook group, which has a lot of cool homemade designs and fixes people have come up with and then printed.