> with(plots):

Warning, the name changecoords has been redefined

> tubeplot([cos(t),sin(t),0],t=0..2*Pi,scaling=constrained,radius=0.4,grid=[30,50],lightmodel=light2);

> a:=tubeplot([cos(t),sin(t),0],t=0..2*Pi,scaling=constrained,radius=0.3,grid=[30,20],color=yellow,lightmodel=light1,title="Y.K.G"):

> b:=tubeplot([0,1+cos(t),sin(t)],t=0..2*Pi,scaling=constrained,radius=0.3,grid=[30,20],lightmodel=light3):

> display(a,b);

> r:=3+cos(t):

> x:=r*cos(s):

> y:=r*sin(s):

> z:=sin(t):

> plot3d([x,y,z],s=0..2*Pi,t=0..2*Pi,scaling=constrained,grid=[30,50],lightmodel=light3);

> restart:

> r:=3+cos(5*t):

> x:=r*cos(s+t):

> y:=r*sin(s+t):

> z:=sin(5*t):

> a:=plot3d([x,y,z],s=0..Pi/5,t=0..2*Pi,scaling=constrained,grid=[10,50],color=red):

> b:=plot3d([x,y,z],s=Pi/5..2*Pi/5,t=0..2*Pi,scaling=constrained,grid=[12,50],color=green):

> with(plots):

> display(a,b);

> restart:

> r:=3+cos(t):

> x:=r*cos(s):

> y:=r*sin(s):

> z:=sin(t):

> plot3d([x,y,z],s=0..2*Pi,t=0..Pi,scaling=constrained,lightmodel=light2,color=yellow,grid=[30,20]);

> restart:

> r:=3+cos(t):

> x:=r*cos(s):

> y:=r*sin(s):

> z:=sin(t):

> plot3d([x,y,z],s=0..Pi,t=0..2*Pi,scaling=constrained,lightmodel=light2,color=yellow,grid=[30,20]);

>