Based on the brilliant Ikea Ivar front mode hook customizable by viljoz I needed to shade my thermostat from direct morning sun.

Instead of a hook, I wrote a module: front_mount() that holds a horizontal wood dowel with my paper flag on it.

Prints without support, but for me the front needed a brim. The front STL is in print orientation: after printing, turn it upside down to use.

The hollow shaft that holds the flag has a chamfer that, at print time, is on the bottom edge so it doesn't need support.