\begin{circus}
\circchannel a, b, c, d, e
\end{circus}

\begin{circus}
\circprocess FE \circdef \circbegin
\end{circus}
\begin{circusaction}
\circspot a \then \Skip \intchoice (a \then \Skip \lpar \lchanset a \rchanset \rpar a \then \Skip)
\end{circusaction}
\begin{circus}
\circend
\end{circus}