\begin{pspicture}(-5,-5)(5,5)
\psset{Decran=50,lightsrc=viewpoint}
\psset{solidmemory}
\psSolid[object=pie,
   h=1,       %% hauteur
   r=1,       %% rayon
   phi=30,    %% angle de debut
   theta=300, %% angle de fin
   ngrid=36 2, %% maillage horizontal et vertical
   fillcolor=yellow,
   name=pie1,
   action=none,
]%
\psSolid[object=pie,
   h=1,       %% hauteur
   r=1,       %% rayon
   phi=300,   %% angle de debut
   theta=390, %% angle de fin
   fillcolor=red,
   name=pie2,
   action=none,
](.3,0,0)%
\psSolid[object=fusion,
   base=pie1 pie2
]
\composeSolid
\end{pspicture}