anchor.diff:            dd
               code.code
                 | dd
  +
  +        dl
  +          dt.div
  +            code.code
  +              | dt.div
  +          dd.div
  +            code.code
  +              | dd.div
   
           dl
             dt.span
  
positive.code:         h1 morph.css
  
          h2
            | .div
  
          ul
            li
              code.code
                | ul li
            li
              code.code
                | li
  
negative.code:             code.code
                | li
  
          ul.div
            li.span
              code.code
                | li.span
            li.span
              code.code
                | li.span
  
          h2
            | dl
  
          dl
            dt
  