Tikz drawing different type of arrows

Question

I am new to the TikZ package, and I need to make this image:

in TikZ.

For now I've done this, and I'm having trouble doing that kind of arrows of image above.

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{shapes,positioning,arrows,calc}
\begin{document}
\tikzset{
    big dot/.style={
            circle, inner sep=0pt, 
            minimum size=3mm, fill=gray
    },
    line/.style={
        draw, 
        line width=1.4pt
    },
        input/.style={
                draw,
                trapezium,
                trapezium left angle=60,
                trapezium right angle=120,
        line width=1.2pt,
        fill={rgb:black,1;white,2}
        },
    obstacle/.style={
                draw,
                trapezium,
                trapezium left angle=120,
                trapezium right angle=60,
        line width=1.2pt,
        fill={rgb:black,1;white,2}
        }
}

\begin{tikzpicture}
\node[input](goal1) at (0,0) {GOAL};
\node[input](goal2) at (4,0) {GOAL};
\node[obstacle](obstacle1) at (0,-1.5) {OBSTACLE};
\node[input](goal3) at (1.5,-3) {GOAL};
\node[input](goal4) at (4,-3) {GOAL};

\draw[line] (goal1.east) -- (goal2.west);
\end{tikzpicture}
\end{document}

Answer 1

This is very easily done with the new arrows.meta library of the CVS version of TikZ (see How to install a current version of TikZ?).

Unfortunately, I cannot create a filled arrow tip of the stealth kind (which can be created with the markings library by first adding a big black tip and then drawing a smaller arrow tip that is colored in over the black one) and the | before it. For reference I used:

arrowS/.style={postaction=decorate,decoration={name=markings, arrow/.list={#1}}},
/pgf/decoration/arrow/.style args={#1:#2-#3}{mark=at position #1 with {\arrow[#2]{#3}}}

which can be used as

arrowS={+-0.01pt:scale=1.7-stealth, +-1.5pt:yellow-stealth}

which worked for my CVS version but the | did not show up. With the stable 2.10 release the | worked but the black stealth tip wasn’t scaled.

You will need to compromise here without using the arrows.meta library.

The flash is simply drawn by the markings library, you can adjust the values, of course.

Code

\documentclass[tikz]{standalone}
\usetikzlibrary{shapes.geometric,arrows.meta,decorations.markings}
\tikzset{
  big dot/.style={circle, draw, inner sep=0pt, minimum size=3mm, fill=yellow},
  input/.style={draw, trapezium, trapezium left angle=60, trapezium right angle=120,
    line width=1.2pt, fill={rgb:black,1;white,2}},
  obstacle/.style={draw, trapezium, trapezium left angle=120, trapezium right angle=60,
    line width=1.2pt, fill={rgb:black,1;white,2}},
  flash/.style args={#1:#2}{postaction=decorate,decoration={name=markings,
    mark=at position #1 with {%
    \draw[fill=#2, line width=.75\pgflinewidth, line cap=round, line join=round]
         (+\pgflinewidth,+7\pgflinewidth)   -- ++ ( left:+2\pgflinewidth) 
      -- (+-4\pgflinewidth,+-\pgflinewidth) -- ++ (right:+5\pgflinewidth)
      -- (+-\pgflinewidth,+-7\pgflinewidth) -- ++ (right:+2\pgflinewidth)
      -- (+4\pgflinewidth,\pgflinewidth)    -- ++ (left:+5\pgflinewidth) -- cycle;}}}
}
\begin{document}
\begin{tikzpicture}[very thick,
  StealthFill/.tip={Stealth[line width=1pt, scale=1.5]}, arrows={[round]}]
\node[input]    (goal1)     at (0,0) {GOAL};
\node[input]    (goal2)     at (4,0) {GOAL};
\node[obstacle] (obstacle1) at (0,-1.5) {OBSTACLE};
\node[input]    (goal3)     at (1.5,-3) {GOAL};
\node[input]    (goal4)     at (4,-3) {GOAL};

\path (goal2) -- node[big dot] (bigdot) {} (goal4);
\path[line width=1.4pt, line cap=rect]
  (goal1) edge[flash=.5:red] (goal2)
  (bigdot) edge (goal3.north)
           edge (goal4)          
           edge[-{StealthFill[fill=yellow]}] (goal2)
  [bend left=10, StealthBar/.style={-{Bar[sep=2] StealthFill[fill=#1]}}]
    (goal2)     edge[StealthBar=green] (obstacle1)
    (obstacle1) edge[StealthBar=red]   (goal2);
\end{tikzpicture}
\end{document}

Output