The Tower of Hanoi with graphics, in LaTeX

bxhanoi.sty

%
% bxhanoi.sty : The "Tower of Hanoi" puzzle shown in graphics
%

%% package declaration
\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{bxhanoi}[2012/02/01]

%% variables
\newcount\bxhp@step
\newcount\bxhp@n@disks
\newcount\bxhp@n@rodA
\newcount\bxhp@n@rodB
\newcount\bxhp@n@rodC
\newcount\bxhp@xx
\newcount\bxhp@yy

%%-------------------------------------- solver logic

%% initialization
\newcommand*\towerofhanoi[1]{%
  \bxhp@n@disks=#1\relax
  \bxhp@init
  \bxhp@cycle\bxhp@exit
}
\def\bxhp@init{%
  \bxhp@step=0
  \bxhp@n@rodA=0 \let\bxhp@rodA\@empty
  \bxhp@n@rodB=0 \let\bxhp@rodB\@empty
  \bxhp@n@rodC=0 \let\bxhp@rodC\@empty
  \loop
    \advance\bxhp@n@rodA 1
    \edef\bxhp@rodA{\bxhp@rodA\the\bxhp@n@rodA/}%
  \ifnum \bxhp@n@rodA<\bxhp@n@disks \repeat
  \ifodd\bxhp@n@disks
    \let\bxhp@cycle\bxhp@cycle@@odd
  \else
    \let\bxhp@cycle\bxhp@cycle@@even
  \fi
  \bxhp@show
}
\def\bxhp@debug@show{%
  \typeout{%
    Step \the\bxhp@step^^J%
    A(\the\bxhp@n@rodA):\bxhp@rodA^^J%
    B(\the\bxhp@n@rodB):\bxhp@rodB^^J%
    C(\the\bxhp@n@rodC):\bxhp@rodC
  }%
}

%% one step
\def\bxhp@cycle@@odd{%
  \bxhp@move AC%
  \bxhp@move AB%
  \bxhp@move BC%
  \bxhp@cycle
}
\def\bxhp@cycle@@even{%
  \bxhp@move AB%
  \bxhp@move AC%
  \bxhp@move BC%
  \bxhp@cycle
}
\def\bxhp@move#1#2{%
  \expandafter\bxhp@move@a
    \csname bxhp@rod#1\expandafter\endcsname
    \csname bxhp@rod#2\endcsname{#1}{#2}%
}
\def\bxhp@move@a#1#2#3#4{%
    %\bxhp@rodX \bxhp@rodY {X} {Y}
  \advance\bxhp@step 1
  \bxhp@let@top\bxhp@topX#1%
  \bxhp@let@top\bxhp@topY#2%
  \ifnum\bxhp@topX<\bxhp@topY
    \def\bxhp@args{#1#2#3#4\bxhp@topX}%
  \else
    \def\bxhp@args{#2#1#4#3\bxhp@topY}%
  \fi
  \expandafter\bxhp@move@b\bxhp@args
}
\def\bxhp@move@b#1#2#3#4#5{%
  \bxhp@pop#1%
  \advance\csname bxhp@n@rod#3\endcsname -1
  \bxhp@push#2#5%
  \advance\csname bxhp@n@rod#4\endcsname 1
  \bxhp@show
  \bxhp@check
}
\def\bxhp@check{%
  \ifnum\bxhp@n@rodC=\bxhp@n@disks
    \expandafter\bxhp@finalize
  \fi
}
\def\bxhp@finalize#1\bxhp@exit{%
  % no-op
}

%%-------------------------------------- stack operation

%% \bxhp@let@top\CS{<stack>}
\def\bxhp@let@top#1#2{%
  \expandafter\bxhp@let@top@a#2\maxdimen/\bxhp@end#1%
}
\def\bxhp@let@top@a#1/#2\bxhp@end#3{%
  \def#3{#1}%
}
%% \bxhp@pop{<stack>}
\def\bxhp@pop#1{%
  \expandafter\bxhp@pop@a#1\bxhp@end#1
}
\def\bxhp@pop@a#1/#2\bxhp@end#3{%
  \def#3{#2}%
}
\def\bxhp@push#1#2{%
  \edef#1{#2/#1}%
}

%%-------------------------------------- drawings

%% color definitions
\definecolor{bxhp@rod}{rgb}{1.0,0.8,0}
\definecolor{bxhp@count}{rgb}{0.0,0.4,0}

%%<*> \tohstepname
% The word for "step".
\newcommand\tohstepname{}

%%<*> \settohunitlength{<dimen>}
% Sets the value of \unitlength used in the puzzle graphics.
\newcommand*\settohunitlength[1]{%
  \def\bxhp@unitlength{#1}%
}

%% \bxhp@draw@figure
\def\bxhp@draw@figure{%
  \begingroup
    \bxhp@xx\bxhp@n@disks \multiply\bxhp@xx6
    \bxhp@yy\bxhp@n@disks \advance\bxhp@yy2
    \setlength\unitlength{\bxhp@unitlength}%
    \begin{picture}(\bxhp@xx,\bxhp@yy)%
      \put(0,0){\color{bxhp@rod}%
        \rule{\bxhp@xx\unitlength}{\unitlength}}%
      \advance\bxhp@yy-1
      \bxhp@xx\bxhp@n@disks \multiply\bxhp@xx2
      \multiput(\bxhp@n@disks,1)(\bxhp@xx,0){3}{%
        \color{bxhp@rod}\kern-.3\unitlength
        \rule{.6\unitlength}{\bxhp@yy\unitlength}}%
      \bxhp@put@tower(\bxhp@n@disks,1){A}%
      \bxhp@xx\bxhp@n@disks \multiply\bxhp@xx3
      \bxhp@put@tower(\bxhp@xx,1){B}%
      \bxhp@xx\bxhp@n@disks \multiply\bxhp@xx5
      \bxhp@put@tower(\bxhp@xx,1){C}%
    \end{picture}%
  \endgroup
}

%% \bxhp@show
\def\bxhp@show{%
  \newpage
  \begingroup
    \noindent\normalsize
    \rule[-1em]{0pt}{3em}\color{bxhp@count}%
    \tohstepname
    \makebox[7em][r]{\bfseries\itshape\LARGE \the\bxhp@step}%
    \par\medskip
    \noindent\normalsize
    \bxhp@draw@figure
    \par
  \endgroup
}

%% \bxhp@elt@disk{<disk_no>}
% Graphics of a disk.
\def\bxhp@elt@disk#1{%
  \@tempdima=.5\p@
  \multiply\@tempdima#1\divide\@tempdima\bxhp@n@disks
  \@tempdimb=.5\p@ \advance\@tempdimb-\@tempdima
  \edef\bxhp@set@color{\noexpand\color
    [rgb]{0,\strip@pt\@tempdimb,\strip@pt\@tempdima}}%
  \@tempdima=1.5\unitlength \@tempdima=#1\@tempdima
  \edef\bxhp@tempa{\the\@tempdima}%
  \makebox[\z@]{\bxhp@set@color\rule{\bxhp@tempa}{\unitlength}}%
}

%% \bxhp@put@tower(x,y){<rod>}
% Puts the whole graphics of a tower in a rod.
\def\bxhp@put@tower(#1,#2)#3{%
  \bxhp@xx=#1\relax \bxhp@yy=#2\relax
  \advance\bxhp@yy\csname bxhp@n@rod#3\endcsname
  \advance\bxhp@yy-1
  \edef\bxhp@args{\csname bxhp@rod#3\endcsname*/}%
  \expandafter\bxhp@put@tower@a\bxhp@args
}
\def\bxhp@put@tower@a#1/{%
  \if*#1\else
    \bxhp@put@tower@b{#1}%
    \expandafter\bxhp@put@tower@a
  \fi
}
\def\bxhp@put@tower@b#1{%
  \put(\bxhp@xx,\bxhp@yy){\bxhp@elt@disk{#1}}%
  \advance\bxhp@yy-1
}

%%-------------------------------------- initial settings
\renewcommand\tohstepname{Step}
\settohunitlength{10pt}

%%-------------------------------------- all done
%% EOF

hanoi10.tex

\documentclass[a4paper]{article}
\usepackage{color} % required
\usepackage{bxhanoi}
\begin{document}
\settohunitlength{5pt} % unit-length in figures
\towerofhanoi{10}      % number of disks
\end{document}