\begin{frame}{Workflow in a Team}
  Mercurial scales from a single team\dots:
  \begin{center}
    \begin{tikzpicture}
      \tikzstyle{repository}+=[minimum height=18mm, text width=12mm]

      \node[repository] (a) at (120:2) {Alice};
      \node[repository] (b) at (240:2) {Bob};
      \node[repository] (c) at (  0:2) {Dev};

      \node[repository, right=of c] (t) {Test};
      \node[repository, right=of t] (p) {Prod};

      \draw[short, <->] (a) -- (c);
      \draw[short, <->] (b) -- (c);
      \draw[short, <->] (c) -- (t);
      \draw[short, <->] (t) -- (p);

      \draw<2>[alert, very thick, ->] (b.west |- 0, -3cm) --
        node[very near start, below] {unstable}
        node[very near end, below] {stable} (p.east |- 0, -3cm);
    \end{tikzpicture}
  \end{center}
\end{frame}