wrap :: Block -> Block
wrap b = Div ("",[],[])
  [ tex $ "%--trim--%\n\\end{pppmulticol}"
  , b
  , tex $ "\\begin{pppmulticol}\n%--trim--%"
  ]
wrap :: Block -> Block
wrap b = Div ("",[],[])
  [ tex $ "%--trim--%\n\\end{pppmulticol}"
  , b
  , tex $ "\\begin{pppmulticol}\n%--trim--%"
  ]
wrap b = Div ("",[],[])
  [ tex $ "%--trim--%\n\\end{pppmulticol}"
  , b
  , tex $ "\\begin{pppmulticol}\n%--trim--%"
  ]