\begin{frame}{Nondeterministic Finite Automata}
    NFAs are defined like DFAs, except that NFAs allow for:
      \item \emph{Multiple starting states}.
      \item \emph{Any number of outgoing arrows} with the same label.
      \item \emph{Empty steps}: arrows labelled $\lambda$ (do not consume input).

    Note that:
      \item both $q_0$ and $q_2$ are starting states
      \item the state $q_1$ has two outgoing arrows with label $b$
      \item there is an empty step from $q_0$ to $q_1$