Here is the ellipsoid x^2/25 ^ y^2/16 +z^2/4=1, labeled with its equation. There is a second .stl file showing the surface without the equation.
This model was designed and printed by my WLU summer research student Emily Jaekle ('16).
This object was made on a MakerBot2X. We used the following settings:
0.20mm layer height
10% infill (hexagonal pattern)
Color matched supports
It is essential to have a raft. The first time we printed this object, it fell over mid-print!