Construct a knot like this: 

Construct a knot like this: 

Construct a chain of five rings each encloses the other four. 
Construct a chain of five rings of the same size each encloses exactly two others. 
Construct the image of the Cartesian grid lines under the
stereographic projection
> with(plots):with(plottools): 
Construct the cyclide by inverting a torus. 
Construct any four mutually tangent spheres of different
sizes. ¡@ ¡@ 
Apply the command "tubeplot" to construct the seashell. 
Construct the astroidal ellipsoid given
by x = (cos u cos v)^{3} y = (sin u cos v)^{3} z = sin^{3}v Reference: A. Gray, Modern Differential Geometry of Curves and Surfaces, p. 304. 
Construct the cupola as thus: 

