\tikzstyle{block} = [draw, fill=blue!20, rectangle,
minimum height=3em, minimum width=6em]
\tikzstyle{input} = [coordinate]
\tikzstyle{output} = [coordinate]
\tikzstyle{pinstyle} = [pin edge={to-,thin,black}]
\begin{tikzpicture}[auto, node distance=4cm,>=latex']
% Placing the blocks
\node [input, name=input] {};
\node [block, right of=input] (controller) {Controller};
\node [block, right of=controller,node distance=3cm] (system) {System};
\node [block, right of=system,node distance=3cm] (system2) {System2};
\node [output, right of=system2] (output) {};
\coordinate [below of=system] (tmp);
% Connecting the nodes
\draw [draw,->] (input) -- node [name=r] {$Input$} (controller);
\draw [->] (controller) -- node[name=u] {} (system);
\draw [->] (system) -- node[name=u] {} (system2);
\draw [->] (system2) -- node [name=y] {$Output$}(output);
\draw [->] (y) |- (tmp) -| (r);
\end{tikzpicture}
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