\begin{circus}
  \circchannel a
\end{circus}

\begin{circus}
  \circprocess  ParSimpleP \circdef \circbegin
\end{circus}

\begin{circusaction}
    A \circdef a \then \Skip
\end{circusaction}

\begin{circusaction}
    \circspot A
\end{circusaction}

\begin{circus}
  \circend
\end{circus}

\begin{circus}
  \circprocess  ParSimpleQ \circdef ParSimpleP \lpar \lchanset a \rchanset
  \rpar ParSimpleP
\end{circus}

\begin{circus}
  \circprocess  ParSimpleR \circdef ParSimpleQ \lpar \lchanset a \rchanset
  \rpar ParSimpleP
\end{circus}
