\documentclass{article}
\usepackage{musixtex}

\begin{document}

\begin{music}
\parindent10mm
\instrumentnumber{1}
\setname1{Piano}
\setstaffs1{1}
\generalmeter{\meterfrac44}
\startextract

% \doublebar

% bar 1
\Notes \qu c \qu d \qu e \qu f \en  \leftrepeat


% bar 2
\Notes \qu g \qu a \qu b \qu c' \en \bar


% bar 3
\Notes \qu g \qu c, \qu b \qu c, \en \bar \rightrepeat



\Notes \qu g \qu c', \qu b' \qu c' \en \endbar  

\endextract
\end{music}

\end{document}