Bunk Bed Cup Holder

For the person on the upper bunk. Will slide over rails up to about 24mm thick. Solid bottom so that drips don't make it to the floor.

If you print this from glow-in-the-dark filament with high infill (even 100%), it will get "charged up" all day with the lights on, then glow for a nice, long time after the lights go out.