> #Klein kancsó (Szabó József modellje, BGYTF, Nyíregyháza)
> restart: with(plots):with(plottools):
>          teteje   := [(2.5+1.5*cos(v))*cos(u), 
>                       (2.5+1.5*cos(v))*sin(u),
>                        -2.5*sin(v)]:
>          kozepe   := [(2.5+1.5*cos(v))*cos(u), 
>                       (2.5+1.5*cos(v))*sin(u),
>                        3*v -6*Pi ]:
>          fogantyu := [ 2 - 2*cos(v) + sin(u), 
>                       cos(u), 3*v -6*Pi ]:
>          alja     := [2 +(2+cos(u))*cos(v), 
>                       sin(u),
>                       -3*Pi+(2+cos(u))*sin(v)]:
>   palack:=plot3d( {teteje,kozepe,fogantyu,alja},
>            u=0..2*Pi,v=Pi..2*Pi,grid=[19,11],
> scaling=CONSTRAINED):

> palack;
> vrml(display3d(palack,color=COLOR(RGB,0.6,0.5,0),
> style=PATCHNOGRID),`palack.wrl`,
> background_color=COLOR(RGB,0,1,1), shininess=0.5, specular_color=COLOR(RGB,0.5,0.5,0.5));