\begin{zed}
NOTAMUSICAL ::= doh | re | mi | fa | sol | la | si
\end{zed}
\begin{circus}
\circchannel acorde : NOTAMUSICAL \cross NOTAMUSICAL \cross NOTAMUSICAL
\end{circus}
\begin{circus}
\circprocess ACXFamily \circdef \circbegin
\end{circus}
\begin{circusaction}
	\circspot 
		(acorde.doh?x.mi \then \Skip \extchoice acorde.doh?x.sol \then \Skip) \circseq acorde?y.re?z \then acorde.doh.mi.sol \then acorde?t?w.fa \then \Skip
\end{circusaction}
\begin{circus}
\circend
\end{circus}
