If you downloaded and printed any of the Prusa topper decoration objects available on thingiverse, you already know what this is good for.
I wanted to be able to print any object and fix it at the top of the Z axis.
So I cut one of the knobs and on meshmixer I did some cleaning and made it a slightly tighten fit.
Just print it by itself and super glue it to any object (of appropriate size, or not...).
(If you are young, don't try to use super glue without supervision. Or use tacky glue instead. ^-^)
PS: The corners of the knob can be put to face the front of the printer. Remember that before attaching to an object.
10% or even zero if you put 3 perimiters (walls)