13-6.html

Construct the torus by pasting two patches as thus:

> restart:

> with(plots):

Warning, the name changecoords has been redefined

> k:=5:

> r:=2+cos(t):

> x:=r*cos(s):

> y:=r*sin(s):

> z:=sin(t):

> s:=u+v:

> t:=k*u:

> a:=plot3d([x,y,z],u=0..2*Pi,v=0..Pi/k,scaling=constrained,color=cyan,grid=[100,20]):

> b:=plot3d([x,y,z],u=0..2*Pi,v=Pi/k..2*Pi/k,scaling=constrained,color=yellow,grid=[100,20]):

> c:=display(a,b):

> c;

[Maple Plot]

> with(plottools):

> vrml(c,"c:/042/13/13-6.wrl",background_color=white);