[pstricks] Intersecting ellipses

[Jan Eden]

Hi fellows,

I know this has been asked just recently, but it slipped my mind: How can I colour the intersection of two forms? In my case, I have two ellipses like this:

\begin{pspicture}*(9,4)
\psellipse(3,2)(3,1)
\rput(2,3.5){epistemische Indizes}
\psline{->}(2,3.2)(2,2)
\psellipse(6,2)(3,1)
\rput(7,0.5){faktische Indizes}
\psline{->}(7,0.7)(7,2)
\rput(4.5,2){\parbox{1.5cm}{\small realistische Indizes}}
\end{pspicture}

I would like to have the intersection ("realistische Indizes") coloured in lightgray while the margins of the ellipses remain visible.

How do I do that?

TIA,

Jan
-- 
A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools.