# Connect parallel lines to node

Sorry guys, I literally can't work out how to do this...

Consider the following figure:

This is drawn by:

  \begin{tikzpicture}
\begin{scope}[rotate=+60]
\foreach \x in {-0.3, -0.2, -0.1, 0.0, +0.1, +0.1, +0.2, +0.3}
\draw[xshift=\x cm] (0, +2) -- (0, 0);
\end{scope}
\begin{scope}[rotate=-60]
\foreach \x in {-0.3, -0.2, -0.1, 0.0, +0.1, +0.1, +0.2, +0.3}
\draw[xshift=\x cm] (0, +2) -- (0, 0);
\end{scope}
\begin{scope}[rotate=180]
\foreach \x in {-0.3, -0.2, -0.1, 0.0, +0.1, +0.1, +0.2, +0.3}
\draw[xshift=\x cm] (0, +2) -- (0, 0);
\end{scope}
\fill[white]      (-1, -1) -- (+1, -1) -- (0, +1) -- cycle;
\draw[very thick] (-1, -1) -- (+1, -1) -- (0, +1) -- cycle;
\draw (0, -0.3) node {+};
\end{tikzpicture}


Now how do I add arrow heads to it? (I want each line to have an arrow head where it meets the triangle.)

As you can see, I already had to to some awful hack with drawing a white triangle over the top of those lines, since TikZ doesn't seem to allow arbitrary clipping. But clipping wouldn't be necessary if I could just make the lines stop at the edge of the triangle --- and that would also make adding arrow heads trivial.

After about an hour of trial and error, I eventually managed to make the syntax for connecting nodes actually work. But then all the lines converge to the center of the triangle, rather than remaining parallel like I want.

\begin{tikzpicture}
\node[name=add, regular polygon, regular polygon sides=3, draw, very thick] at (0, 0) {+};
\begin{scope}[rotate=60]
\foreach \x in {-0.3, -0.2, -0.1, 0.0, +0.1, +0.1, +0.2, +0.3}
\draw[xshift=\x cm, ->] (0, +2) to (add);
\end{scope}
\end{tikzpicture}


Any hints?

• Please try with \draw[<-] (add.60)--+(60:2cm);. Writting tikz code from an ipad is not so easy. – Ignasi Jan 26 '15 at 21:27
• @Ignasi Very true. And in the past it was even worse – JLDiaz Jan 27 '15 at 15:11

You can use the anchors to position your arrows, and, as @Ignasi suggests, specify coordinates in terms angles.

# MWE

\documentclass[border=2pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{shapes.geometric}

\begin{document}
\begin{tikzpicture}
\node(add)[regular polygon,regular polygon sides=3,draw,very thick,minimum size=2cm]{+};
\foreach\ang[count=\i] in {60,180,300}{
\begin{scope}[rotate=\ang]
\foreach \x in {0,.1,.2,.3}{