Things were getting a bit hot behind my home-lab rack, so I figured additional cooling was needed. I slammed together the geometry of 3 of @KennyVerhoeve_588554 's blanking plates in order to get the requisite size, made some holes to mount fans, and fan grills, then used 3 120mm computer case fans I had laying around.
I used this fan controller from amazon to power the fans (https://www.amazon.com/dp/B0BLMF8GMC), but any generic fan controller will probably work fine. When mounted with rubber screws, the fans had enough play that I could just jam the knob between two of them, and the excess wires in the other gap, as pictured, without needing double sided tape.
The pre-sliced files include a color change in order to get the multicolor effect to the fan grills, joints, and rings around the grates. I found that supports were not needed for the decorative ring around the grates, but a little support was needed for the edge of the joints to make sure they didn't sag.
After printing, the sides will need to have the joints where they meet the center either sanded or cut back a bit with a chisel, if you want the face to be perfectly flush. I didn't bother, and you actually can see the secondary color in the joint if you just let it sit proud, which I liked when I test-fit it.
I used the rubber screws included with the fans to mount them, but if yours didn't come with them, you could use either heat-set threaded inserts and m4 machine screws to mount the fans, or use the (untested) rubber grommets I included printed out of FLEX, and thread M4 screws directly into those for a bit of vibration dampening. If you do try that method, let me know if it works…
The author remixed this model.