TeXnical notes
Sometimes I find a solution to a TeXnical problem, and I think everybody should know about it. Some of these things are totally obvious, but (as far as I know) non-standard.
You may also want to check out my advice on real-time TeXing.
BibTeX without a separate .bib file
How to draw the Fox-Artin wild arc with pstricks
\documentclass{article}
\usepackage{pstricks}
\usepackage{multido}
\begin{document}
\[\begin{pspicture}(-7.6,-.5)(7.32,2.5)
\newdimen\totaljump % This measures where the orgin is
\newdimen\jumpinterval % This measures how much the origin moves each time
%%%%% First we draw the left hand side. Because we are utilizing borders, we have %%%%%
%%%%% to draw from left to right, so compute by hand what the unit should be. %%%%%
\psset{unit=0.17293822569mm,border=.05,linewidth=.03}
\totaljump=-75mm
\jumpinterval=0.17293822569mm
\multido{}{20}{
% Move the origin to the appropriate place %%%%
\psset{origin={\totaljump,0}, unit= 1.25, border=.05, linewidth=.03}
% Draw a piece of the curve
\pscurve(-.1,.1)(-.2,.3)(0,1.5)(1,.7)(2.3,.3)(2,-.05)(1.1,-.2)(1,-.1)
% Scale the jumpinterval by .8 and increment totaljump
\multiply\jumpinterval by 5 \divide\jumpinterval by 4
\advance\totaljump by \jumpinterval
}
%%%% Now we draw one piece of the curve in the middle %%%%
%%%% to get the two ends to match up nicely. %%%%
\psset{unit=1.5cm,border=.05,linewidth=.03}
\pscurve(-.15,.12)(-.2,.3)(0,1.7)(1,.7)(1.8,.3)(1.6,-.05)(1.1,-.2)(.95,-.15)
%%%% Now draw the right hand side %%%%
\psset{origin={12mm,0}}
\totaljump=12mm
\jumpinterval=12mm
\multido{}{20}{
\advance\totaljump by \jumpinterval
\multiply\jumpinterval by 4 \divide\jumpinterval by 5
\pscurve(-.1,.1)(-.2,.3)(0,1.5)(1,.7)(1.6,.3)(1.4,-.05)(1.1,-.2)(.9,-.1)
\psset{origin={\totaljump,0}, unit= .8, border=.05, linewidth=.03}
}
\end{pspicture}\]
\end{document}
Placing labels on arrows in XY-pic
(I learned this trick from Aaron Lauda; I haven't seen it documented anywhere)
\xymatrix{asdfasdf \ar[r]^{f} & a }
produces the label "f" in a stupid place, half-way between the centers of the two entries, instead of where you'd like it to be, half-way along the arrow. One way to handle this is to do something like
\ar[r]^(.7){f}
but that is fairly unsatisfying because you have to calibrate the (.7) by eye. There is another way, which is to use
\ar[r]^-{f}
which will automatically place the label "f" half-way along the arrow. If you want the label .7 of the way along the arrow, you can do
\ar[r]^-(.7){f}