What is the most bizarre thing you have seen done with TeX

Question

I think the questions says it all! :)

By TeX, I mean any derivative of TeX as long as the code is clearly a derivative of TeX, i.e. that it could belong on TeX.SX (and not pure Lua for example).

I'll give two answers myself so you see what I mean.

Answer 1

I think that Steve Hicks controller for a Mars Rover programmed in TeX is a good candidate: ICFP Contest 2008 - Mars rover in TeX.

Answer 2

Adding coffee stains to your documents

If my documents don't have those stains, my boss / students think(s) I don't drink coffee. If he or they think I am not drinking coffee, they believe I am slacking. Thanks Hanno!

Answer 3

David Carlisle's Christmas 'card' at http://www.ctan.org/pkg/xii. In fact, here it is: run this through plain TeX:

\let~\catcode~`76~`A13~`F1~`j00~`P2jdefA71F~`7113jdefPALLF
PA''FwPA;;FPAZZFLaLPA//71F71iPAHHFLPAzzFenPASSFthP;A$$FevP
A@@FfPARR717273F737271P;ADDFRgniPAWW71FPATTFvePA**FstRsamP
AGGFRruoPAqq71.72.F717271PAYY7172F727171PA??Fi*LmPA&&71jfi
Fjfi71PAVVFjbigskipRPWGAUU71727374 75,76Fjpar71727375Djifx
:76jelse&U76jfiPLAKK7172F71l7271PAXX71FVLnOSeL71SLRyadR@oL
RrhC?yLRurtKFeLPFovPgaTLtReRomL;PABB71 72,73:Fjif.73.jelse
B73:jfiXF71PU71 72,73:PWs;AMM71F71diPAJJFRdriPAQQFRsreLPAI
I71Fo71dPA!!FRgiePBt'el@ lTLqdrYmu.Q.,Ke;vz vzLqpip.Q.,tz;
;Lql.IrsZ.eap,qn.i. i.eLlMaesLdRcna,;!;h htLqm.MRasZ.ilk,%
s$;z zLqs'.ansZ.Ymi,/sx ;LYegseZRyal,@i;@ TLRlogdLrDsW,@;G
LcYlaDLbJsW,SWXJW ree @rzchLhzsW,;WERcesInW qt.'oL.Rtrul;e
doTsW,Wk;Rri@stW aHAHHFndZPpqar.tridgeLinZpe.LtYer.W,:jbye

A good collection of Enjoy TeX pearls diving! at GUST, Polish TeX Users Group

For more Pearls of TeX programming at TUGboat ,Volume 26 (2005), No. 3.

Answer 4

a basic interpreter written in tex.

see the tugboat article.

Answer 5

Our own Bruno LeFloch who wrote a Reversi game which runs in the console:

(Please don't try to reformat the code displayed below unless you really know what you are doing; if you do attempt a reformat, try to compile the resulting code before replacing the code here.)

% !TEX TS-program = tex
\long\def\3#1#2#3{}\vsize5cm\hsize4cm\newlinechar`*\def~#1{\catcode`#113~}
~QSU_VWJKLMNO@XY[](|+Z'"z:qj^;/)!,\ ${*13\3}
\def~#1#2{\let#1#2~}~*\cr[\ifnum(\ifcaseO\or|\else]\fiN\number@\advanceX
\expandafterZ\globalY\message~\defj{[0<Q[9>Q[0<J[9>J^|_]|_]|_]|_]}
~+{\count1}+1=9~_#1{@+1 1\countdef#1+1_}_QJVSKWUL,'"$\H!_-1'1"2+44'+55'+45"+54"~^{+NQNJ}
~:#1{#11#12#13#14#15#16#17#18}
~M#1{Y{#1}#1}~\h#1#2{M#2:{ \q#1}&M#2&M{*}}~\q#1#2{&M{(+#1#2  O-O0]}}
~/{Y{Row and column? e.g. E6*}\read_to\MX\j\meaning\M  ;}
~\j#1->#2#3#4;{Q`#2@Q-`@J`#3@J-`0;(VY{Invalid move.}
/]}~;{V0 (jS1z1z0z_S0z1z_S_z1z0z_]}~\_{@,('O-]}
~z#1{{\H0K#1!1{\H1q}(!q]}}~q{@QS@JK[j="(\HZ^'Z\_2]\&q|[j='ZVV($(\H|Z!0]]]]}~\,#1{Q#1:\.}
~\.#1{J#1;[0<V\&[V>WWVUQLJ]]}~\^#1{(#1O0O1O2O2O2O2O1O0]}
~\&{!\^Q\multiply!3@!\^J@V(!9O1O6O1O1O2O6O2O4] }~\Z{M :{&M}&M{*}}
~){'X"X"N'\halign{&## *M{*}
\Z\h1A\h2B\h3C\h4D\h5E\h6F\h7G\h8H\Z}
\vfil\break$1W(W_|0] :\,$0 [0<W[1='QUJL|/];^'\_1][_=WM
{(,Tie| Player [0>,-|0] wins by N[0>,-],].}X\end])})

Answer 6

I once spent hours learning enough TeX to format my ex-gf's resume for printing on the computing center laser printer (back when laser printing was magical) and used up most of my monthly laser printing quota printing copies of it -- all under the mistaken belief that she'd see that she was crazy to break up with me.

Not surprisingly, it turned out to be a useless waste of my time (and in retrospect, it was me that should have broken up with her). Worse, word got around that I was a "TeX expert" and I ended up spending the rest of my computer center operator job helping grad students format their theses

Answer 7

Solving a non-linear equation

Not typesetting the solution (actually, also typesetting the solution of course :)), but more bizarrely implementing the bisection and secant non-linear solvers in TeX!

Answer 8

This one is probably my best:

• Is there a documentclass that produces 'endless' pages? (please take a look at percusse's comment - pure genius! :))

But there are a few of them scattered around on this site. Here are my picks:

• Shortest code causing "Emergency stop." error

• Stop LaTeX compile with a command?

• Selectively suppress generation of typeset output

• Typesetting the entire Song That Never Ends

• Malicious code and/or PDF generation

• Forcing LaTeX to produce a different PDF on each compile (never reaching a stable output)

... and, as a bonus:

• How should I convert my beamer slides to PowerPoint according to these odd specifications?

I really don't see why someone would go back to MS Office after using LaTeX... Now that's weird! ;)

EDIT: and i just remembered this one (Why facebook implemented it? But why recreate it in LaTeX? ;)):

• Text upside-down, characters rotated along baseline?

Answer 9

Calculating π with TeX

Gen­er­ates π, us­ing the for­mula

pi=16*arc­tan(1/5)-4*arc­tan(1/239)

and leaves the re­sult in an ar­ray \xr, print­ing what it’s cal­cu­lated as it goes along.

Answer 10

Well, as made famous by a question of mine I have used LaTeX to make to make props for a Call of Cthulhu game. I also posted the finished product on my blog.

Then later on I used the same technique to make my teaching assistant's life a bit more interesting

Answer 11

Implementing the bisection method (and other numerical methods) in TikZ,
for exposition purposes.

EDIT: Great thanks to percusse for helping me improve my \ifg command.

\documentclass[dvipsnames]{beamer}

\usepackage{lmodern}
\usepackage{pgfplots}

\usefonttheme[onlymath]{serif}
\setbeamertemplate{navigation symbols}{}

% 'if #1 greater than #2 then #3 else #4' construct (compatible with pgfmath)
\newcommand{\ifg}[4]{
    \pgfmathparse{(#1)>(#2)?int(1):int(0)}
    \ifnum\pgfmathresult=1relax%
        #3%
    \else%
        #4%
    \fi%
}

\begin{document}

\begin{frame}[fragile]
    \begin{center}
    \begin{tikzpicture}[scale=6]
    \pgfmathsetmacro{\extendxaxis}{.1}
    \pgfmathsetmacro{\extendyaxis}{.3}
    \colorlet{acolor}{red}
    \colorlet{bcolor}{OliveGreen}
    \colorlet{ccolor}{orange}
    \colorlet{fcolor}{blue}
    \pgfmathdeclarefunction{f}{1}{\pgfmathparse{.5*(exp(-#1)-#1)}} % continuous function
    \pgfmathsetmacro{\ao}{.2}   % lower-bound of initial bracket
    \pgfmathsetmacro{\bo}{1}    % upper-bound of initial bracket
    \pgfmathsetmacro{\co}{0}    % midpoint of inital bracket (initialised at 0)
    \pgfmathtruncatemacro{\n}{3}        % number of iterations

    \ifx\ao\bo % check that \ao and \bo are distinct 
        \node[red] (0,0) {Bisection impossible: singleton initial bracket.};
    \else%
        \ifg{\ao}{\bo}{ % if \ao > \bo, swop them
            \pgfmathsetmacro{\temp}{\bo}
            \pgfmathsetmacro{\bo}{\ao}
            \pgfmathsetmacro{\ao}{\temp}
        }{}
        % code in here
        \ifg{{f(\ao)*f(\bo)}}{0}{%
            \node[red] (0,0) {Bisection impossible: no root in initial bracket.};
        }{%
            \onslide<1->{%
                \pgfmathsetmacro{\xmin}{\ao-.5*\extendxaxis*(\bo-\ao)}
                \pgfmathsetmacro{\xmax}{\bo+.5*\extendxaxis*(\bo-\ao)}
                \draw[->] (\xmin,0) node[left] {$0$} --
                    (\xmax,0) node[right] {$x$};
                \pgfmathsetmacro{\ymin}{min(f(\ao),f(\bo))-.5*\extendyaxis*abs(f(\bo)-f(\ao))}
                \pgfmathsetmacro{\ymax}{max(f(\ao),f(\bo))+.5*\extendyaxis*abs(f(\bo)-f(\ao))}
                \draw[->] (\xmin,\ymin) -- (\xmin,\ymax) node[left] {$f(x)$};
                \draw[fcolor] plot[domain=\xmin:\xmax] (\x,{f(\x)});
            }
            \pgfplotsforeachungrouped \k in {1,2,...,\n}{%
                \pgfmathtruncatemacro{\k}{\k}
                \pgfmathsetmacro{\co}{0.5*(\ao+\bo)}
                \pgfmathtruncatemacro{\j}{\k-1}
                \pgfmathtruncatemacro{\fromslide}{3*(\k-1)+2}
                \pgfmathtruncatemacro{\toslide}{\fromslide+2}
                \onslide<\fromslide-\toslide>{
                    \draw[thick,acolor] (\ao,.1ex) --
                        (\ao,-.1ex) node[below] {$a_{\j}$}; % a0
                    \draw[thick,bcolor] (\bo,.1ex) --
                        (\bo,-.1ex) node[below] {$b_{\j}$}; % b0
                }
                \pgfmathtruncatemacro{\fromslide}{\fromslide+1}
                \onslide<\fromslide-\toslide>{%
                    \draw[thick,ccolor] (\co,.1ex) --
                        (\co,-.1ex) node[below] {$c_{\j}$};     
                }
                \onslide<\toslide>{%
                    \coordinate (a0) at (\ao,{f(\ao)});     
                    \draw[dashed,thin,red]  (a0 |- \xmin,0) -- (a0)
                        -- (a0 -| \xmin,0) node[left] {$f(a_{\j})$};% dashed lines
                    \draw[fill,red] (a0) circle (.05ex);            
                    \coordinate (c0) at (\co,{f(\co)}); 
                    \draw[dashed,thin,orange]   (c0 |- \xmin,0) -- (c0)
                        -- (c0 -| \xmin,0) node[left] {$f(c_{\j})$};% dashed lines      
                    \draw[fill,orange] (c0) circle (.05ex);                                 
                }
                \ifg{f(\ao)*f(\co)}{0}{ % bisection iteration
                    \pgfmathsetmacro{\ao}{\co}
                }{%
                    \pgfmathsetmacro{\bo}{\co}
                }
                \ifx\n\k%
                    \pgfmathtruncatemacro{\toslide}{\toslide+1}
                    \pgfmathtruncatemacro{\j}{\j+1}
                    \onslide<\toslide>{%
                        \draw[thick,acolor] (\ao,.1ex) --
                            (\ao,-.1ex) node[below] {$a_{\j}$}; % a0 
                        \draw[thick,bcolor] (\bo,.1ex) --
                            (\bo,-.1ex) node[below] {$b_{\j}$}; % b0 
                    }
                \fi                     
            }
        }
    \fi
    \end{tikzpicture}
    \end{center}
\end{frame}
\end{document}

Answer 12

Providing an excuse for slacking off

Just let (La)TeX burn some CPU cycles while you are relaxing.

Answer 13

Enrico “egreg” Gregorio posted this into our TeX.sx chat:

1. Let me name it xcix.tex, because it’s in the manner of David Carlisle’s xii.tex, cf. Peter Flynn’s answer

   \let~\catcode~`x13~`q~`x~`z~`q~`H~`q~`B~`H~`j0~`jA009
   jlet~jlet~Hjpar ~Bjmscount~~jdef~x{q bottlez of beer}
   ~jw{x on the wall}~jt{jadvanceAB-1ATake one down Aand
   pass it around,H}B99~ji{jifnumB}~q{ji=0Nojelsejnumber
   Bjfi}~z{ji>1sjfiA }jloop jifnumB>0 jw, x,Hjtjw.jvskip
   8ptplus1ptjrepeat Time to buy some more beerjdotsjend
   

   (source link)

2. The same as LaTeX3 version

   \documentclass{article}
   \usepackage{xparse}
   
   \setlength{\parindent}{0pt}
   \setlength{\parskip}{1.5ex}
   
   \ExplSyntaxOn
   % user level command
   \NewDocumentCommand{\beers} { O{99} }
    {
     \manual_beers_sing:n { #1 }
    }
   % variables
   \int_new:N \l_manual_beers_count_int
   % functions
   \cs_new_protected:Npn \manual_beers_sing:n #1
    {
     \int_set:Nn \l_manual_beers_count_int { #1 }
     \prg_replicate:nn { \l_manual_beers_count_int }
      {
       \manual_beers_print:
       \int_decr:N \l_manual_beers_count_int
      }
     Time ~ to ~ buy ~ some ~ more ~ beer ~ \dots
    }
   \cs_new_protected:Npn \manual_beers_print:
    {
     \manual_beer_text:nn { ~ on ~ the ~ wall }{ 0 }, ~
     \manual_beer_text:nn { } { 0 }, \\
     Take ~ one ~ down ~ and ~ pass ~ it ~ around, \\
     \manual_beer_text:nn { ~ on ~ the ~ wall } { -1 }.\par
    }
   \cs_new:Npn \manual_beer_text:nn #1 #2
    {
     \int_case:nnF { \l_manual_beers_count_int + #2 }
      {
       { 0 } { No ~ bottle ~ of ~ beer }
       { 1 } { 1 ~ bottle ~ of ~ beer }
      }
      {
       \int_to_arabic:n { \l_manual_beers_count_int + #2 } ~ bottles ~ of ~ beer
      }
     #1
    }
   \ExplSyntaxOff
   \begin{document}
   \beers
   \end{document}
   

   (source link, small correction; the code as seen above is, though, in this version, as it will appear in a manual by Enrico, which is in the moment, this code was posted, in process of writing)

This was influenced by me, because I had posted these two links:

• 99 Bottles of Beer | Language TeX/LaTeX (for compilation read comment of Kiyoshi Akima below that code)

• 99 Bottles of Beer | Language LaTeX2e loading fmtcount and tikz
  (which has a link to an older version 99 Bottles of Beer | Language LaTeX2e working with memoir and loading only ifthen)

Answer 14

Implementing a Turing machine simulator
(TeX is Turing complete)

Hail to the busy beaver!

Answer 15

At this stage, having seen a lot of bizarre things done with LaTeX by users :-) I should probably add the bookshelf package I posted to CTAN recently.

This takes a BiBTeX file (eg your thesis) and turns it into an image of a bookshelf so you can use it as a background during video calls; in my case to cover up the fact that my bookshelves were hideously untidy :-)

Answer 16

The avremu package

…emulates an 8-bit CPU (ATmega8).