\begin{circus}
\circchannel a : \nat \cross \nat \cross \nat
\end{circus}
\begin{circus}
\circprocess P1 \circdef \circbegin
\end{circus}
\begin{circusaction}
\circspot
a.5.6?x \then \Skip
\end{circusaction}
\begin{circus}
\circend
\end{circus}
\begin{circus}
\circprocess P2 \circdef \circbegin
\end{circus}
\begin{circusaction}
\circspot
a.5.6!3 \then \Skip
\end{circusaction}
\begin{circus}
\circend
\end{circus}
\begin{circus}
\circprocess NotMS \circdef P1 \lpar \lchanset a \rchanset \rpar P2
\end{circus}