title: Filled and hollow shapes where the fill color = the line color
body: <p>I want to convey three types of information in a dot-plot. I can use color, shape and fill (my actual data has too many points to use size effectively). But it would look best if the fill color was the same as the outline color.</p>
  
  <p>The closest I can get is this:</p>
  
  <pre><code>data(mtcars)
  p &lt;- ggplot(mtcars,aes(x=mpg,y=wt))+
    geom_point(aes(color=factor(cyl),shape=factor(gear),fill=factor(vs)))+
    scale_fill_manual(values=c("black",NA))+scale_shape_manual(values=c(21,22,23))
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/2OTQd.png" alt="enter image description here"></p>
  
  <p>which fills black into all outline colors, ugly. Any ideas on how to fill the red points with red and the blue points with blue?</p>