§@·~8

1.Construct the torus using the command "tubeplot".
2.Construct two tori as thus:
3.Construct the torus using the command "plot3d".
4.Construct the torus by pasting two patches as thus:
5.Construct one half of a torus so its cross-section consists of two concentric circles.
6.Construct one half of a torus so its cross-section consists of two disjoint circles.
7.Construct one half of a torus so its cross-section consists of two intersecting circles.
8.Construct one half of a torus so its cross-section consists of two interlocking circles in space.
9.Construct a knot as thus:
10.Construct knots as thus:
11.Construct a twisted torus whose sections are formed by regular triangles: