\documentclass{beamer}
\usepackage{tikz}
\setbeamertemplate{navigation symbols}{}
\begin{document}

  \begin{frame}
   \frametitle{Notes}
   \begin{center}
   \begin{tikzpicture}
    \foreach \y in {0,1,2,3,4,5,6}
     \draw[thick] (0,\y) -- (11,\y);
   \end{tikzpicture}
   \end{center}
  \end{frame}
\end{document}