Diagram draw with xy package looks wrong

Question

I'm trying out the xy package and have compiled one of the examples on this website: http://en.wikibooks.org/wiki/LaTeX/Creating_Graphics#Xy-pic

\begin{displaymath}
    \xymatrix{
        A \ar[d] \ar[dr] \ar[r] & B \\
        D                       & C }
\end{displaymath}

But when I compile the latex code with latex test.tex and look at the resulting test.dvi, I get this:

The arrow pointing to the bottom right looks wrong. How do I fix this?

EDIT: Here's the full latex code:

\documentclass[12pt]{article}
\usepackage[all]{xy}
\begin{document}
\begin{displaymath}
  \xymatrix{
    A \ar[d] \ar[dr] \ar[r] & B \\
    D                       & C }
\end{displaymath}
\end{document}

Answer 1

By compiling with pdflatex you can use the package xypdf

\documentclass[12pt]{article}
\usepackage[all]{xy}
\usepackage{xypdf}
\begin{document}
\begin{displaymath}
  \xymatrix{
    A \ar[d] \ar[dr] \ar[r] & B \\
    D                       & C }
\end{displaymath}
\end{document}

One important comment by Matsaya:

after test, I want to say that xypdf is now an integrated to xy. Indeed, when you try to compile the examples of the xypdf manual with pdfLaTeX and the new xy package, it works just fine (the same as with the old fashion way xy + xypdf).