# Is there a simple way to get the Bourbaki dangerous bend symbol (without extra)?

I would like to put a Bourbaki dangerous bend symbol in my text. The LaTeX package manfnt allows to easily type the Knuth variant of the Bourbaki dangerous bend symbol. This variant is basically the Z-shaped dangerous band inside a signal diamond attached to a pole (\dbend). This variant is nice but height: it introduces extra interline (because of the pole). I am looking for a Z-shaped only version, a one that is ready to use.

• this is unicode U+2621 so it should be in the stix/xits fonts. – barbara beeton Aug 21 '15 at 14:43
• @barbarabeeton Is that an uppercase U I see before me? – user10274 Aug 21 '15 at 14:46
• @MarcvanDongen -- uh, yes. (there are some exceptions.) – barbara beeton Aug 21 '15 at 14:53
• @barbarabeeton Very interesting: any hint on how to type it in LaTeX ? – Spherical Triangle Aug 21 '15 at 15:04
• for the stix fonts, the command \danger was proposed, but i'm not sure it's the final choice. – barbara beeton Aug 21 '15 at 15:34

A TikZ version with the height of a "Z". Width, height, rotation angle, line thickness, ... can easily be changed.

\documentclass{article}
\usepackage{tikz}

\begin{document}
\tikz[
line cap=but,
line join=round,
x=.5em,
very thick,
y=1*(height("Z")-\pgflinewidth)*(1-sin(10)),
rotate=-10,
rounded corners=1.5pt,
]\draw (1, 0) -- (0, 0) -- (1, 1) -- (0, 1);
\end{document}


This implements Barbara Beeton's suggestion without loading the stix package:

\documentclass{article}

\DeclareFontFamily{U}{stixbbit}{}
\DeclareFontShape{U}{stixbbit}{m}{it}{<-> stix-mathbbit}{}
\DeclareRobustCommand{\stixdanger}{%
{\usefont{U}{stixbbit}{m}{it}\symbol{"F6}}%
}

\begin{document}

This is the \stixdanger{} symbol.

\end{document}


• I like the slightly rotated version, partly because it's more clear that it's not a letter Z or a numeral 2. To get the rotation, it worked for me to use \rotatebox[origin=c]{-10}{\stixdanger}, with rotatebox being provided by the graphicx package. – Ben Crowell Nov 22 '18 at 20:09

Find its unicode, see the fonts which support it, search your system for available fonts and do (Lua- or XeLaTeX needed):

% arara: pdflatex

\documentclass{article}
\usepackage{fontspec}

\begin{document}
\fontspec{code2000.ttf}\symbol{"2621}
\fontspec{quivira.otf}\symbol{"2621}
% or very dangerous...
\fontspec{symbola.ttf}\symbol{"2621}
\end{document}


Following @barbarabeeton comment, a stix version writes:

\documentclass{article}
\usepackage{stix}

\begin{document}
$\danger$
\end{document}

• Unfortunately the package stix interferes very badly with my target journal template (article document + AmS packages): does a more selective package exist ? ((Note: I am ready to hack for own stuff, but I am not sure about the Journal editorial team behaviour: past experiences convince me to stick to classical stuff)) – Spherical Triangle Aug 21 '15 at 18:24
• It seems like egreg's answer would be a variation on this that would avoid the clash with the stix package. – Ben Crowell Nov 22 '18 at 19:56

Inspired in Egreg's answer below I present my own Bourbaki's dangerous bendsymbol:

\DeclareFontFamily{U}{stixbbit}{}
\DeclareFontShape{U}{stixbbit}{m}{it}{
<-> stix-mathbbit
}{}
\DeclareSymbolFont{stixbbit}{U}{stixbbit}{m}{it}
\DeclareMathSymbol{\bend}{\mathord}{stixbbit}{"F6}
\newcommand*{\bendsymbol}{\ensuremath{\bend\hspace{-2mm}\bend\hspace{-2mm}\bend\hspace{-2mm}\bend}}


The original symbol would be the \bend symbol defined. I want it thicker too, that's why I define also the \bendsymbol symbol. It is true that it isn't the most elegant way to get it. However, it has (what I think is) and advantage with respect to Egreg's bend symbol, and is that it's defined as a math ordinary symbol, just like \alpha.

It is possible to rotate it if one wants, but I like it just like that.