Noctua NF-F12 Fan Stand & Platform

thingiverse

You can use this to elevate a Noctua NF-F12 fan off of a surface and then also use another as a platform on the other side of the fan. It comes apart really easily, so you could use something like hot glue or melt the posts a bit to make them bulge if you don't want that happening. Haven't done any fancy math in terms of airflow/grille size/etc, just kinda went with a grille size that could hold stuff easily and an elevation that wasn't too inconvenient.