The structure of the collection of processes may be pictured as
\setlength{\unitlength}{0.01cm}
\nop{
)
}
\hspace{0.4cm}
\mbox{
\begin{picture}(1000,350)(0,0)
\put(200,200){\circle{100}}
\put(400,200){\circle{100}}
\put(600,200){\makebox(0,0){}}
\put(800,200){\circle{100}}
\put( 250,200){\vector(4,0){ 100}}
\put( 450,200){\vector(4,0){ 100}}
\put( 650,200){\vector(4,0){ 100}}
\put(200,100){\makebox(0,0){driver}}
\put(400,100){\makebox(0,0){sieve1}}
\put(800,100){\makebox(0,0){}}
\end{picture}
}\n
where each arrow represents a channel.