# How can I make a circle with an arrow entering/leaving it?

I'm wondering how could I make a symbol (in math mode) that looks more or less like this:

I need to introduce some symbols for my thesis, to represent some sets of elements that are 'entry points' and 'exit points' of some clusters, and I've used already too many letters of mathcal and mathscr, so for the sake of clarity, I'd like to have some symbols that 'talk' to the readers.

I've tried to find an existing symbol using detexify without success.

So I think the next step is to somehow build it myself, and I have too little experience in it to manage to create them (I can have the arrow above or below the circle, I can't have it entering or exiting the circle)

• Depending on what font you are using and exactly how you want it to look, you may look at the various symbols and arrows encoded in Unicode, for instance: ⮊ U+2B8A RIGHTWARDS BLACK CIRCLED WHITE ARROW – Kess Vargavind Jul 2 '19 at 8:51

\documentclass[tikz,border=3.14mm]{standalone}
\begin{document}
\begin{tikzpicture}
\draw[line width=1mm] (-155:0.5) arc (-155:155:0.5)
(-0.5,0) -- (0.25,0) (0.05,0.2) -- (0.25,0) -- (0.05,-0.2);
\end{tikzpicture}
\end{document}


Or as a symbol. See the answers to this question for more details. This symbol becomes large if you use \large and so on.

\documentclass{article}
\usepackage{tikz}
\newcommand{\mysymbol}{\begin{tikzpicture}[baseline=-0.27em]
\draw[line width=0.07em] (-155:0.3em) arc (-155:155:0.3em)
(-0.3em,0) -- (0.15em,0) (0.05em,0.1em) -- (0.15em,0) -- (0.05em,-0.1em);
\end{tikzpicture}}
\begin{document}
X \mysymbol\ x
\end{document}


Or with another finish (of course using clip and not overpainting white, which will look bad on a nonwhite background).

\documentclass{article}
\usepackage{tikz}
\newcommand{\mysymbol}{\begin{tikzpicture}[baseline=-0.27em]
\begin{scope}
\clip (-0.4em,0.1em) -| (0,-0.1em) -| (-0.4em,-0.4em) -| (0.4em,0.4em)
-| cycle;
\end{scope}
\draw[line width=0.07em] (-0.3em,0) -- (0.15em,0) (0.025em,0.125em) --
(0.15em,0) -- (0.025em,-0.125em);
\end{tikzpicture}}
\begin{document}
X \mysymbol\ x {\Large X \mysymbol\ x}

{\Huge X \mysymbol\ x} {\small X \mysymbol\ x}

\end{document}


• Thanks, the symbol really looks like what I had in mind :-) Do you think there is a way to make it the equivalent of a math symbol, so there is the possibility to add indices to it, place them in sums and fractions, etc ... ? I use tikz for figures, so I know very little on how to use it to make symbols once the drawing exsits. – m.raynal Jul 2 '19 at 8:36
• @m.raynal Yes, look at the answers to tex.stackexchange.com/q/480768/121799. You basically need to make everything in units of em or ex. If my internet connection allows it I will give it a shot. – user121799 Jul 2 '19 at 8:40
• In case it is useful to someone, here is the code to make the same symbol, but with the arrow leaving the circle on the right side: \draw[line width=0.07em] (25:0.3em) arc (25:335:0.3em) (0.05em,0) -- (0.45em,0) (0.35em,0.1em) -- (0.45em,0) -- (0.35em,-0.1em); And thanks a lot, @marmot :-) you made (at least a part of) my day – m.raynal Jul 2 '19 at 9:08