title: Spread out density plots with ggplot
body: <p>I saw this great plot from fivethirty that has a slight overlap of density plots for different colleges.  Check out <a href="http://fivethirtyeight.com/features/the-most-conservative-and-most-liberal-elite-law-schools" rel="nofollow noreferrer">this link at fivethirtyeight.com</a></p>
  
  <p>How would you replicate this plot with <em>ggplot2</em>? </p>
  
  <p>Specifically how would you get that <strong>slight overlap</strong>,  <em>facet_wrap</em> isn't going to work.</p>
  
  <pre><code>TestFrame &lt;-  
    data.frame(
      Score =
        c(rnorm(100, 0, 1)
          ,rnorm(100, 0, 2)
          ,rnorm(100, 0, 3)
          ,rnorm(100, 0, 4)
          ,rnorm(100, 0, 5))
      ,Group =
        c(rep('Ones', 100)
          ,rep('Twos', 100)
          ,rep('Threes', 100)
          ,rep('Fours', 100)
          ,rep('Fives', 100))
    )
  
  ggplot(TestFrame, aes(x = Score, group = Group)) +
    geom_density(alpha = .75, fill = 'black')
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/YfbQb.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/YfbQb.png" alt="Partially overlaid density"></a></p>