This is the case for my mini magic mirror project. You can find the complete build video at: https://youtu.be/2POMz7ta9uw
The pyramid has a hole in the back for a USB cable to run through, and the frame fits the Kuman 3.5" LCD that has an HDMI Port (I Haven't tested it on other LCD's yet, if you do please let me know). The build video explains it pretty well, but basically this LCD Frame press fits into the pyramid, and then you hot glue a magic mirror onto the LCD. It's a very simple build.
This could also be used as a simple desktop holder for a Pi Zero with an LCD (no magic mirror necessary). The four holes were for Neodymium magnets, but I ditched that idea. I left them there in case I decide to go back to it, since with a mirror on the front it didn't hurt.
The pyramid is a bit 'burly'...my attempts at making it thinner resulted in various issues. As it is it took me 87 grams of filament to print, so please be aware.
Amazon Basic PLA
This was designed in Tinkercade. This is currently my 10th revision of the LCD holder, and probably about 6th of the pyramid.