Done with EMT and the following code.

>u=linspace(-1,1,100); ...
> v=linspace(0,2*pi,500)'; ...
> X=(3+u*cos(v/2))*cos(v); Y=(3+u*cos(v/2))*sin(v); Z=u*sin(v/2);
>view(2,1,0°,20°); fullwindow();  ...
>twosides(false); plot3d(X,Y,Z,grid=[40,5]):
>function one (x0,y0,z0,a,b,f=1,z=0.8) ...
$global X,Y,Z;
$xa=(X-x0)*f; ya=(Y-y0)*f; za=(Z-z0)*f;
$fullwindow; view(0,z,a,0);
$plot3d(xa,ya,za,<frame,<scale,grid=[40,5]);
$endfunction
>one(3,0,0.1,0,0,1):
>function two (t,f=1,z=0.9) ...
$global X,Y,Z;
$x0=3+cos(t+pi/2)*0.1; y0=0; z0=sin(t+pi/2)*0.1;
${x0,y0}={x0*cos(2*t)-y0*sin(2*t),x0*sin(2*t)+y0*cos(2*t)};
$one(x0,y0,z0,2*t,0,f,z);
$endfunction
>two(2):
>function three () ...
$t=linspace(0,2pi,30);
$for s=t;
$   two(s); wait(0);
$end;
$endfunction
>three
>load makeanimations
 Functions to make an animated GIF or an MPEG movie.
>makegif("two",linspace(0,2pi,50),"anim",600);