I am trying to draw multiple outputs system with TiKz but I'm having several problems to get it right.I have searched for examples, but I could not find anything that looks like to what I want to draw. So far I had tried (code shown below), but the outcome doesn't satisfy me.
\begin{tikzpicture}
\tikzstyle{startstop} = [rectangle, rounded corners, minimum width=3cm, minimum height=1cm,text centered, draw=black, fill=red!30]
\tikzstyle{startstop2} = [circle, minimum width=1.8cm,,text centered, draw=black, fill=blue!30]
\tikzstyle{startstop3} = [rectangle, rounded corners, minimum width=3.5cm, minimum height=1cm,text centered, draw=black, fill=yellow!30]
\tikzstyle{arrow} = [thick,->,>=stealth]
\node (a) [startstop] {a};
\node (b) [startstop2,xshift=5cm] {b};
\node (c) [startstop,xshift=10cm] {c};
\node (d) [startstop3,xshift=5cm,yshift=3cm] {d};
\draw [arrow] (a) -- (b);
\draw [arrow] (b) -- (c);
\draw [arrow] (d) -- (b);
\draw [arrow] (d.south west) -- (b.north west);
\draw [arrow] (d.south east) -- (b.north east);
\end{tikzpicture}
It would be something like the following:
What should I write in Latex for the multiple arrows ??