%@AUTEUR: Juergen Gilg

\begin{pspicture}(-4,-11)(-6,7)
\psset{solidmemory}
\psset{unit=0.75}
\psset{lightsrc=10 5 10,SphericalCoor,viewpoint=20 10 20,Decran=50}

\defFunction{F}(t){t cos 3.2 mul}{t sin 3.2 mul}{}
\defFunction{G}(t){t 3 add cos 3 mul}{t 3 add sin 3 mul}{}
\defFunction{H}(t){t cos 0.8 mul}{t sin 0.8 mul}{}
\defFunction{I}(t){t 12 add cos 0.6 mul}{t 12 add sin 0.6 mul}{}
\defFunction{J}(t){t cos 1.55 mul}{t sin 1.55 mul}{}
\defFunction{K}(t){t 6 add cos 1.4 mul}{t 6 add sin 1.4 mul}{}

\psSolid[%
    object=ruban,
    h=0.5,
    fillcolor=red,
    incolor=lightgray,
    base=0 6 360 {/Angle exch def Angle F Angle G} for,
    ngrid=1,
    solidmemory=true,
    action=none,
    name=outer,
    ](0,0,0)
\psSolid[%
    object=ruban,
    h=1.2,
    fillcolor=blue,
    incolor=gray,
    base=0 24 360 {/Angle exch def Angle H Angle I} for,
    ngrid=1,
    solidmemory=true,
    action=none,
    name=inner,
    RotZ=-95,
    RotX=90
    ](0,1.25,0)
\psSolid[%
    object=ruban,
    h=0.3,
    fillcolor=green,
    incolor=gray,
    base=0 24 360 {/Angle exch def Angle H Angle I} for,
    ngrid=1,
    solidmemory=true,
    action=none,
    name=inner1,
    RotZ=-120,
    RotX=90
    ](0,0,0)
\psSolid[%
    object=ruban,
    h=0.7,
    fillcolor=yellow,
    incolor=lightgray,
    base=0 12 360 {/Angle exch def Angle J Angle K} for,
    ngrid=1,
    solidmemory=true,
    action=none,
    name=inner2,
    RotZ=45 2 mul neg
    ](0,0,0)
\psSolid[%
    object=fusion,
    base=inner1 inner2 inner outer,
    name=spiro,
    action=draw**
    ](0,0,0)%
\composeSolid


\end{pspicture}