[texhax] symbol for triple vertical 'x'

[Robin Fairbairns]

> > thanks for your help - I modified your code slightly to make the 'x's
> > smaller and it looks fine for my purposes
> >
> > \newcommand{\recur}{\hbox to 1ex{\hbox to0pt{\raisebox{0.9ex}{\sffamily
> > \tiny x}}%
> > \hbox to0pt{\raisebox{-0.3ex}{\sffamily \tiny x}}%
> > \hbox to0pt{\raisebox{0.3ex}{\sffamily \tiny x}}}}
> >
> >
> > There's just one strange bug: a blank line preceding a \recur starts a
> > new paragraph after the triple 'x' sign.
> > Has anyone got any ideas as to the cause of this phenomenon?
> 
> It's something I've come across before but always been too lazy to fully
> understand: it's something to do with LaTeX's handling of \hbox's.  Anyway,
> none of the suggestions I made in the previous posting has this problem.

not latex, tex.  if you're in vertical mode, an \hbox is added, on its
own, to the vertical list, and you stay in vertical mode.  any
following text will then start a new paragraph in the ordinary way.

latex box "\hbox" commands (like \mbox, \framebox and so on) all emit
\leavevmode to avoid this slightly startling behaviour.  which doesn't
stop pretty much *anyone* from slipping "bare" \hbox on to innocent
users from time to time.  (i've done it myself.)