This is a four level Menger Sponge. Made completely in Blender. I made it because all the models I found online were in other formats, and importing them often left much to be desired. Completely public domain... use them however you wish.
there is already a plugin in default blender you can enable to make these of any level.
There sure is. I never noticed it before. Oh, well. OTOH, my 4-level has 54k fewer vertices and 56k fewer faces than the one that the plug-in creates. It was a fun project in any case. Maybe I'll upload my Sierpinski gasket... I don't see one of them in Blender.