> restart;
> x:=cos(t);
> y:=sin(t);
> z:=t/5;
> w:=min(max(z+s,2*Pi/5),4*Pi/5);
>plot3d([x,y,w],t=0..15,s=0..2*Pi/5-0.03,grid=[101,5]);

> restart;
> x:=cos(t);
> y:=sin(t);
> z1:=1+cos(2*t);
> z:=u*z1;
> plot3d([x,y,z],t=0..2*Pi,u=0..1,scaling=constrained,grid=[41,5]):

> restart;
> x:=r*cos(t);
> y:=r*sin(t);
> z:=x^2-y^2+1;
> p1:=plot3d([x,y,z],t=0..2*Pi,r=0..1,grid=[31,11]):
> x:=cos(t);
> y:=sin(t);
> z1:=1+cos(2*t);
> z:=u*z1;
> p2:=plot3d([x,y,z],t=0..2*Pi,u=0..1,scaling=constrained,grid=[31,5]):
> with(plots):
>display(p1,p2):

> restart;
> Re(3+4*I);
> Re(x+I*y);
> z:=x+I*y;
> expand(z^3);
> x:=r*cos(t);
> y:=r*sin(t);
> z:=x^3-3*x*y^2+1;
> plot3d([x,y,z],t=0..2*Pi,r=0..1,grid=[41,7]):

> restart;
> Re(3+4*I);
> Re(x+I*y);
> z:=x+I*y;
> expand(z^3);
> x:=r*cos(t);
> y:=r*sin(t);
> z:=x^3-3*x*y^2+1;
> p1:=plot3d([x,y,z],t=0..2*Pi,r=0..1,grid=[31,7]):
> x:=cos(t);
> y:=sin(t);
> z1:=1+cos(3*t);
> z:=u*z1;
> p2:=plot3d([x,y,z],t=0..2*Pi,u=0..1,scaling=constrained,grid=[31,5]):
> with(plots):
> display(p1,p2):

> restart;
> with(plots):
> x:=cos(t);
> z:=sin(t);
> y1:=x;
> y2:=-x;
> y:=(1-u)*y1+u*y2;
> p1:=plot3d([x,y,z],t=0..2*Pi,u=0..1,scaling=constrained,color=red):
> p2:=plot3d([y,-x,z],t=0..2*Pi,u=0..1,scaling=constrained,color=blue):
> display(p1,p2):
　

> restart;
> with(plots):
> x:=cos(t);
> z:=sin(t);
> y1:=x;
> y2:=-x;
> y:=(1-u)*y1+u*y2;
> p1:=plot3d([x,y,z],t=0..Pi,u=0..1,scaling=constrained,color=red,grid=[17,17]):
> p2:=plot3d([y,-x,z],t=0..Pi,u=0..1,scaling=constrained,color=blue,grid=[17,17]):
> display(p1,p2):

> restart;
> with(plots):
> x:=cos(t);
> z:=sin(t);
> y1:=x;
> y2:=-x;
> y:=(1-u)*y1+u*y2;
> p1:=plot3d([x,y,z],t=-Pi/2..Pi/2,u=0..1,scaling=constrained,color=red,grid=[15,15]):
> p2:=plot3d([y,-x,z],t=-Pi/2..Pi/2,u=0..1,scaling=constrained,color=blue,grid=[15,15]):
> p:=display(p1,p2):

> restart;
> t:=3*s;
> a:=1;
> b:=2;
> c:=sqrt(a^2+b^2);
> z1:=a*sin(t);
> r1:=c+a*cos(t);
> x1:=r1*cos(s);
> y1:=r1*sin(s);
> z2:=a*sin(t+Pi);
> r2:=c+a*cos(t+Pi);
> x2:=r2*cos(s);
> y2:=r2*sin(s);
> w:=expand((1-u)*[x1,y1,z1]+u*[x2,y2,z2]);
> plot3d(w,u=0..1,s=0..2*Pi,scaling=constrained,grid=[5,61]):