Popcorn Fan Mounts

Attaches to popcorn joint - allows you to connect a fan by using a bolt (or screw) through the corner hole of a fan. Useful in helping hands.
UPDATE: I have included a right and left hand version of this joint both with and without a cable path.
Update improved STL

Not quite what you wanted? Feel free to tweak these designs.
The tinkercad source files are published here: https://tinkercad.com/tags/popcorn