Level 4 Menger Sponge

A level-four Menger Sponge. This printed in just under three days on my Prusa i3 clone, at 0.1mm layer height, 100% infill, and conservative motion settings.

Large file is large -- make sure you have plenty of memory and give it time to load, if you open the F360 file. It may not be anywhere near optimal; I'm still a F360 beginner. Simplify3D had no trouble with the .stl file.

The undersides of the four large overhangs at the top level don't print well without support. My printer was eventually able to bridge the gap much like a spider building a web, but the undersides of those parts don't look pretty. You may want to use custom support here.