anchor.diff:                %|tr
                   %|th "colspan" => 2
                     Hello World
  +            %|tfoot
  +              %|tr
  +                %|th
  +                  Good
  +                %|th
  +                  Bye!
               %|tbody
                 %|tr
                   %|td
  
positive.code:                   %%|tr
                      %%|th "colspan" => 2
                        Hello World
                  %%|tbody
                    %%|tr
                      %%|td
  
negative.code:                   %%|tr
                      %%|td "style" => "color: blue"
                        Qux
  
            Would appear like this in a web browser:
  
  