# How to enter symbol consisting of 4 points

I am reading Elementary Topology Problem Book O. Viro, et al. I came across to this curious symbol (which I have annotated in the screenshot below):

Is it possible to type this symbol in TeX? I am asking because I am currently taking notes while studying from this book, and it would be great if I could type the exact symbol as shown.

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If you like, draw it in a separate program (not my strong point) in a TeX-friendly format, and create a command to include it as needed (e.g., \includegraphics[height=\baselineskip]{<image>.png}). – jon Oct 30 '13 at 2:38
Ask Viro for the tex code for his book. – Benjamin McKay Oct 31 '13 at 8:03

You could create your own symbol using tikz and adjust the parameters as desired:

## Notes:

• The baseline=0.25ex was used to shift the symbol below the baseline.

## Code:

\documentclass{article}
\usepackage{amsmath}
\usepackage{tikz}

\newcommand*{\CircleSize}{0.6pt}%
\newcommand{\MySymbol}{\mathbin{\tikz [x=0.5em,y=1.4ex,line width=.2ex, baseline=0.25ex] %
\draw [line width=0.4pt, fill=black]
(0.60,0.75) circle (\CircleSize) --
(0.30,0.0) circle (\CircleSize) --
(0.00,0.5) circle (\CircleSize) --
(0.00,1.1) circle (\CircleSize)
;}}%
\begin{document}
We denote the space of the Problem by $\MySymbol$.
\end{document}

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The top edge on the left branch seems to be slanted. Or is it just an optical illusion? – kiss my armpit Oct 30 '13 at 6:56
the symbol in the original example has a depth that looks to be just a bit lower than the descender on "y". this drawing sits on the baseline. – barbara beeton Oct 30 '13 at 9:16
Why is the symbol in math mode? – gerrit Oct 30 '13 at 10:57
@Marienplatz: In my version it is slanted (for some reason that is what I thought was required). But if you replace the last 0.10 with 0.00 it won't be slanted. – Peter Grill Oct 30 '13 at 21:13
@gerrit: It does not need to be -- that is just how I prefer my symbols (as they are almost always in math mode). – Peter Grill Oct 30 '13 at 21:15

How about making the symbol of your own (called \myownsymbol) where you may want to move it vertically by raisebox technique (here opt is set for the baseline). This is inspired by How do I define a new punctuation mark?. (Thanks to those authors.)

Code:

\documentclass[]{article}
\usepackage[papersize={15cm,4cm}]{geometry}
\usepackage{tikz}
\newcommand\mysymbol{%
\tikz{%
\node[circle,fill,inner sep=0.5pt] (A) at (0,0){};
\node[circle,fill,inner sep=0.5pt] (B) at (-2pt,3pt){};
\node[circle,fill,inner sep=0.5pt] (C) at (-2pt,6pt){};
\node[circle,fill,inner sep=0.5pt] (D) at (2pt,4pt){};
\draw (D)--(A)--(B)--(C);
}
}
\newsavebox{\mysymbolbox}
\savebox{\mysymbolbox}{\mysymbol}
\newcommand{\myownsymbol}{\raisebox{0pt}\kern1pt \usebox{\mysymbolbox}\kern-2pt}}

\begin{document}

\vspace{5cm}

This is my own symbol\myownsymbol.

We denote the space of Problem 2.3 (1) by \myownsymbol. It is a sort of toy space made of 4 points.
\end{document}

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The exact symbol with PSTricks just for fun!

\documentclass[preview,border=12pt]{standalone}
\usepackage{pst-tree}

\def\icon#1{%
\psscalebox{#1}{%
\psTree[treemode=U,levelsep=1]{\TC*}
\psTree{\TC*}
\TC*
\endpsTree
\psTree[levelsep=.5]{\Tn}
\TC*
\endpsTree
\endpsTree}}

\begin{document}
Problem \textit{2.3} (1) by \icon{.15}.
\end{document}


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