I printed half of a Sierpinski octahedron with six levels. It turned out very nice! If you want to print one too the file is on Thingiverse (not my design).
I made it 200mm which is bigger than the original design and I used Hilbert curve top and bottom layers. Why not go all in on fractals? It took around 152 hours to print, used around 700 grams of filament, and it took around 20 minutes to slice with a beefy computer. I was worried about printing a 297MB G-code file from an SD card but it did great.
I think the last time I posted in the show and tell is when I assembled the printer. Maybe this is a good time to do an update on that. In the 165 days since then it has been printing for 132 days (3,168 hours and 12 minutes to be exact). It has been a joy to use and extraordinarily reliable. If you’re considering getting a 3D printer then check out the Prusa i3 MK3 kit.