Slips on a common (USA) recessed ceiling light to limit the light or glare in 1 direction. This one shrouds 120 degrees, at about 90mm. The kitchen light in the photo bothered her when sitting in her favorite chair. It could easily be scaled in Prusa Slicer.
I printed this on a Prusa XL, using Printed Solid's Jessie PLA in Design White with a 3d honeycomb fill at 20% for an interesting pattern. Could be printed solid for even more light blocking.
FreeCad file included. FC Version 1.0 is awesome.
The author marked this model as their own original creation.