\newcommand{\nodebox}[5]{%
  \rput(0,0){\rnode{#1}{\psframebox[#2]{\rule{0pt}{#4}\hspace{#3}}}}
  \rput(0,0){\psframebox[fillstyle=none,linestyle=none]{\parbox{#3 -
        0.3cm}{\centering #5}}}
}
\newpsstyle{process}{shadow=false,fillstyle=solid}

\begin{pspicture}(0,0)(16,8)%\showgrid
\rput(-1.85,0){\small
  \psset{xunit=3.4cm,yunit=1.1cm}
  \def\boxwidth{2.4cm}
  \def\boxheight{0.75cm}

  % draw the boxes
  \rput(2,6.5){\nodebox{nVirgin}{style=process}{\boxwidth}{\boxheight}%
    {Virgin Production}}
  \rput(2,5.5){\nodebox{nRecyc0}{style=process}{\boxwidth}{\boxheight}%
    {Recycling}}

  \rput(3,6){\nodebox{nUse}{style=process}{\boxwidth}{\boxheight}%
    {Use}}
  \rput(4.8,6){\nodebox{nDisp}{style=process}{\boxwidth}{\boxheight}%
    {Disposal}}

  \rput(1,3.9){\nodebox{nScrap1}{style=process}{\boxwidth}{\boxheight}%
    {Scrap Collection}}
  \rput(3,3.9){\nodebox{nScrap2}{style=process}{\boxwidth}{\boxheight}%
    {Scrap Collection}}
  \rput(2,3){\nodebox{nRecyc1}{style=process}{\boxwidth}{\boxheight}%
    {Recycling}
    \pnode(0.7,0){nRecyc1p}}
  \rput(2,2){\nodebox{nPP1}{style=process}{\boxwidth}{\boxheight}%
    {\scriptsize Primary Production}
    \pnode(0.7,0){nPP1p}}
  \rput(2,1){\nodebox{nOth1}{style=process}{\boxwidth}{\boxheight}%
    {\scriptsize Production of other materials}
    \pnode(0.7,0){nOth1p}}
  \rput(4,3){\nodebox{nRecyc2}{style=process}{\boxwidth}{\boxheight}%
    {Recycling}
    \pnode(0.7,0){nRecyc2p}}
  \rput(4,2){\nodebox{nPP2}{style=process}{\boxwidth}{\boxheight}%
    {\scriptsize Primary Production}
    \pnode(0.7,0){nPP2p}}
  \rput(4,1){\nodebox{nOth2}{style=process}{\boxwidth}{\boxheight}%
    {\scriptsize Production of other materials}
    \pnode(0.7,0){nOth2p}}
  
  % draw the arrows
  \psset{arrowsize=3pt 3,arrowlength=1.1,arrowinset=0.15,linearc=0.07}
  \ncdiag[angleA=0,armA=0,angleB=180,armB=0]{->}{nVirgin}{nUse}
  \ncdiag[angleA=0,armA=0,angleB=180,armB=0]{->}{nRecyc0}{nUse}

  \ncangle[angleA=0,angleB=90]{->}{nUse}{nRecyc2}
  \ncline{->}{nUse}{nDisp}
  \ncangle[angleA=0,angleB=90]{->}{nScrap2}{nRecyc2}
  \ncangle[angleA=0,angleB=180]{->}{nScrap1}{nRecyc0}
  \ncangle[angleA=0,angleB=180]{->}{nScrap1}{nRecyc1}
  
  \ncline{->}{nRecyc1}{nRecyc1p}
  \ncline{->}{nRecyc2}{nRecyc2p}

  \ncline{->}{nPP1}{nPP1p}
  \ncline{->}{nPP2}{nPP2p}

  \ncline{->}{nOth1}{nOth1p}
  \ncline{->}{nOth2}{nOth2p}
}

% graphic blandishment
\psframe[linewidth=0.7pt](0,0)(16,5.25)
\psframe[linewidth=0.7pt](0,0)(16,8)

\end{pspicture}