And just for the fun of it…..
Doesn’t this ellipsoid of revolution (below to the left) look a lot like Pepperidge Farm’s Milano cookie (right)?
How it works ?
The following applet illustrates a spheroid (ellipsoid of revolution) with equation (x2 /a2)+(y2 /b2)+ (z2 /b2)=1, for the case where a>=b. The white points are foci, the orange points are vertices, and the yellow point is any point on this ellipsoid of revolution. (Feel free to drag this yellow point anywhere you’d like!)