title: Want to create a mapping or chart for showing many to many mapping
body: <p>I am trying to show <code>many to many</code> mappings on user Interface. I have mapping in database which I am trying to plot on user Interface.</p>
  
  <p>I will explain with an example. </p>
  
  <p>suppose, there are two area of <code>studies</code> - A and B. And a user Sam has answered some questions from Study Area "A". </p>
  
  <p>And now he want to see that by answering those question in study area "A" what are the question in study area "B" he has already covered. So the mapping can be like this. </p>
  
  <pre><code>A.1 --- B.3
  
  A.1 --- B.4
  
  A.2 --- B.1
  
  A.2 --- B.3
  
  A.4 --- B.2 
  
  A.4 --- B.3
  
  A.4 --- B.1
  </code></pre>
  
  <p>Now I have tried using sankey <code>diagram</code> and parallel <code>coordinates</code> and modified them for two columns, </p>
  
  <p>But the problem is they are looking very clumsy when the columns have more number of rows and data is also not readable. So can you suggest some techniques to present this to user in any way? </p>
  
  <p>It can be <code>charts</code>, <code>mappings</code>, <code>grids</code> etc.</p>