It turns out the Prusa MK4 weighs enough to squish my add-on foam feet to about half their original thickness:
The two in the front are 30×30 mm and the shorter (more squished) foot was under the right rear of the MK4 where the power supply lives.
The larger feet (one installed) are 60×60 mm and, with the same weight supported on four times the area, should squish much less.
Stipulated: I can’t hear the difference either way.
This project was precipitated by finding a large scrap of exercise mat foam in a place where it shouldn’t have been.
The Smell of Molten Projects in the Morning 
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