Prototype Model

\begin{figure}
  \center
  \begin{tikzpicture}[
    nd/.style={draw, rounded corners, minimum height=1cm, minimum width=3cm, fill=white},
    line/.style={thick},
  ]
    \node (com) [nd] {Communication};
    \node (qp)  [nd, right=of com] {Quick Plan}
      edge [<-, line] (com);
    \node (qd)  [nd, below=of qp] {Quick Design}
      edge [<-, line] (qp);
    \node (pc)  [nd, below left=of qd] {Prototype Construction}
      edge [<-, line] (qd);
    \node (dep) [nd, left=of qd] {Deployment \& Feedback}
      edge [<-, line] (pc)
      edge [->, line] (com);
  \end{tikzpicture}
  \caption{The Prototyping design model.}
  \label{fig:prototyping}
\end{figure}