Superimposed Boxes in a flowchart with PStricks

Question

I'm performing a flowchart using pstricks . The problem is how to do superimposed Boxes (in gray and light gray ) included in the flow chart like those in the picture below . Is there any specific function to produce that ?

This is what I've done so far

    \begin{psmatrix}[rowsep=0.4,colsep=0.5]
\psovalbox[fillstyle=solid,fillcolor=yellow,shadow=true]{Begin} \\
    \psframebox[shadow=true]{Initialisations} \\
    \psdiabox[fillstyle=solid,fillcolor=Pink,shadow=true]{Special} &
       \psframebox[shadow=true]{1)} & \psframebox[shadow=true]{2)} \\
    \psframebox[shadow=true]{Action 1} \\
    ~\\
    \psframebox[shadow=true]{Action 2} \\
    \psovalbox[fillstyle=solid,fillcolor=yellow,shadow=true]{End}
    % Links
    \ncline{->}{1,1}{2,1}
    \ncline{->}{2,1}{3,1}
    \ncline{->}{3,1}{4,1}<{\textcolor{red}{No}}
    \ncline{->}{4,1}{6,1}
    \ncline{->}{6,1}{7,1}
    \ncline{->}{3,1}{3,2}^{\textcolor{red}{Yes}}
    \ncline{->}{3,2}{3,3}
    \ncbar[angleA=-90,armB=0,nodesepB=0.25]{->}{3,3}{4,1}
\end{psmatrix} 

Thank You for your help in advance .

Answer 1

To create such a background have a look at the examples at the pstricks example page: http://tug.org/PSTricks/main.cgi?file=pst-node/psmatrix/psmatrix

To create such a background you must nest three psframe:

\documentclass[pstricks]{standalone}
%\documentclass{article}
\usepackage{pstricks,multido}
\usepackage{pst-node}
\usepackage{pstricks-add}
\begin{document}
\begin{pspicture}(-1.5,-1.5)(6.5,4.5)
\pnode(0,0){A}
\pnode(6,4){B}
\psset{fillstyle=solid}
\psframe[fillcolor=gray!20](A)(B)
\uput[-135](B){\huge$m$}
\nodexn{(A)-.5(1,1)}{A}
\nodexn{(B)-.5(1,1)}{B}
\psframe[fillcolor=gray!40](A)(B)
\uput[-135](B){\huge$\ldots$}
\nodexn{(A)-.5(1,1)}{A}
\nodexn{(B)-.5(1,1)}{B}
\psframe[fillcolor=gray!60](A)(B)
\uput[-135](B){\huge$1$}
\end{pspicture}

\end{document}