TeXでシェルピンスキー・ギャスケットを作る http://doratex.hatenablog.jp/entry/20140522/1400688261

Sierpinski.tex

\documentclass{minimal}
\usepackage{graphicx}
\usepackage{xcolor}
\usepackage{pgffor}
\usepackage{etoolbox}
\usepackage{varwidth}
\usepackage[active,tightpage]{preview}

\PreviewEnvironment{varwidth}
\setlength{\PreviewBorder}{0pt}

\setlength{\parindent}{0pt}
\setlength{\fboxsep}{2pt}

\newbox\ZERO
\newbox\ONE
\def\outputletter#1{%
  \ifvmode\leavevmode\fi
  \ifcase#1\copy\ZERO\or\copy\ONE\fi
}

\begin{document}

\setbox\ZERO\hbox{\colorbox[RGB]{170,255,255}{\makebox[7pt][c]{\texttt{0}}}}
\setbox\ONE\hbox{\colorbox{red}{\textcolor{white}{\makebox[7pt][c]{\texttt{1}}}}}

\begin{varwidth}{\maxdimen}
\begin{center}
\setlength{\lineskiplimit}{-\maxdimen}
\setlength{\baselineskip}{10pt}

\outputletter{1}

\outputletter{1}\outputletter{1}

\csnumgdef{C0}{1}
\csnumgdef{C1}{1}
\foreach \n in {2,...,127}{%
  \outputletter{1}%
  \csnumgdef{t}{\n-1}%
  \csnumgdef{p}{1}%
  \foreach \i in {1,...,\t}{%
    \csnumgdef{q}{\csname C\i\endcsname}%
    \csnumgdef{C\i}{\p+\q}%
    \ifnum\csname C\i\endcsname>1
      \csnumgdef{C\i}{\csname C\i\endcsname - 2}%
    \fi
    \csnumgdef{p}{\q}%
    \outputletter{\csname C\i\endcsname}%
  }%
  \csnumgdef{C\n}{1}%
  \outputletter{1}\par
}
\end{center}
\end{varwidth}
\end{document}