No supports. No bridging. No retractions. It has the astonishing property that the horizontal cross sections are simply connected and change continuously with height, so can be printed perfectly with spiral mode (or single-walled without infill).

This fractal is half of the octahedron flake (or Sierpinski octahedron). Every triangular face is a Sierpinski triangle, and the base of the pyramid is (approximately) a space-filling curve called the Sierpiński curve. Figures like the Vicsek fractal also exist in this model.