This fan duct will redirect air flow from 120mm/140mm fan at an angle.
For example this can be used
Air is deflected by 60° at bottom, and 45° at the top of the fan.
You can choose version with or without teeth. Benefit of teeth is not clear. Teeth might reduce noise in some cases, but harder to print.
OpenSCAD source is also included. Please let me know if you know better implementation of path_extrude, this one might be slightly buggy in corner cases (but works fine in this case).
The author marked this model as their own original creation.