Egg middle cross-section is hex based. It can be printed without support material: only brim is necessary. My model was done with Prusament PLA, 0.2 mm regular slicing. Tolerance on shell rim is 0.3 mm, so the remaining's of brim should be well removed.

Wen small magnet is put inside (5 x 2.5 mm), the egg will easy become a “Columbus egg”: it will stand vertically on metallic surface.

STL file in binary format contains two parts.