Construct a knot like this: 

Construct a knot like this: 

Construct a knot based on the
parametric representation [cos 3t, sin 4t, sin 5t] 

Construct a knot based on the
parametric representation [cos 13t, sin 4t, sin 17t] 
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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): 
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. 