[Xy-pic] binary trees

[Andreas Bauer]

Hello Ross,

> The Xy-pic Reference Manual explains the parsing of the
> argument of \xygraph. It provides a simple "escape" mechanism
> to use arbitrary Xy-pic kernel code, when this is an appropriate
> way to add features into the diagram.

Thanks for taking the time to reply. It almost looks as I imagined it, except 
the stars in the corners should be _real_ corners. I guess, if there's no 
other way then I'll go with your solution without quesitoning it much. On the 
other hand, if there's an existing template that creates nice triangles then 
I would like to see it :-)

Cheers,
Andi.

-- 
Andreas Bauer, baueran _at_ in.tum.de, http://home.in.tum.de/baueran/
"Science without religion is lame; religion without science is blind."
  -- Albert Einstein