
   Troff hello world
  ===================

  
   o set left margin -> ".po" command
   o set right margin -> ".ll" command
   o set the top of the page -> ".mk" (+ traps)
   o back to the top of the page -> ".rt" (+ traps)
   o font type/size/weight, line-height, justification...
  
  That is mostly it! No "element" nor "block" in troff: no <div>
  
