\begin{frame}{Exercise}
  \begin{goal}{}
    An arrow with label \alert<1>{$a,b$} is shorthand for two arrows:
    one with label $a$ and one with label $b$.
  \end{goal}

  \begin{minipage}{.40\textwidth}
    \begin{tikzpicture}[default,node distance=20mm,->]
      \node (q0) [fstate] {$z_0$}; \draw ($(q0) + (-10mm,0mm)$) -- (q0); 
      \node (q2) [state,right of=q0] {$z_2$};
      \begin{scope}[node distance=20mm]
      \node (q1) [fstate,above of=q2] {$z_1$};
      \end{scope}
      
      \draw (q0) to node [label,above left] {$a$} (q1);
      \draw (q0) to[bend left=10] node [label,above] {$b$} (q2);
      \draw (q1) to[bend left=10] node [label,right] {\alert<1>{$a,b$}} (q2);
      \draw (q2) to[bend left=10] node [label,left] {$a$} (q1);
      \draw (q2) to[bend left=10] node [label,below] {$b$} (q0);
    \end{tikzpicture}
  \end{minipage}\pause%
  \begin{minipage}{.60\textwidth}
    \begin{exampleblock}{}
      What is this DFA?
      \begin{itemize}\setlength{\itemsep}{-.5ex}
      \medskip
        \item states $Q = \mpause[1]{\{\,z_0,z_1,z_2\,\}}$
      \medskip
        \item alphabet $\Sigma = \mpause{\{\,a,b\,\}}$
      \medskip
        \item transition function $\delta : Q \times \Sigma \to Q$\,:
          \begin{center}
            {\renewcommand{\arraystretch}{1}
            \begin{tabular}{c|cccc}
              $\delta$ & $z_0$ & $z_1$ & $z_2$\\
              \hline
              $a$ & \mpause{$z_1$} & \mpause{$z_2$} & \mpause{$z_1$} \\
              $b$ & \mpause{$z_2$} & \mpause{$z_2$} & \mpause{$z_0$}
            \end{tabular}}
          \end{center}
      \medskip
        \item
        starting state \mpause{$z_0$}
      \medskip
        \item
        final states $F = \mpause{\{\,z_0,z_1\,\}}$
      \medskip
      \end{itemize}
    \end{exampleblock}
  \end{minipage}
\end{frame}