Quadrics Pics

ellipsoid#1 x^2/4+y^2+z^2=1

ellipsoid#2 x^2+y^2/4+z^2/4=1

ellipsoid#3 x^2/4+y^2/9+z^2=1

circular paraboloid z=x^2+y^2

elliptical paraboloid z=2x^2+y^2 

hyperbolic paraboloid or saddle z=x^2 - y^2

hyperboloid of one sheet x^2+y^2-z^2=1

hyperboloid of two sheets x^2+y^2-z^2= -1