title: Pattern fills for graphs
body: <p>As <code>ggplot2</code> produces nice colored graphs but sometimes it is required to have black and white graphs with <a href="http://blogs.office.com/b/microsoft-excel/archive/2007/11/16/chart-pattern-fills.aspx">pattern fills</a>. I wonder how to do this in <code>ggplot2</code>, say for this code:</p>
  
  <pre><code>ggplot(diamonds, aes(cut, fill=cut)) + geom_bar()
  </code></pre>
  
  <p><strong>Edit</strong></p>
  
  <p>Is there any function in <code>R</code> to do pattern fills for graphs?</p>