Start floating display.
That is, if the amount of space
required to output text exceeds the space remaining on the current
page, the display is saved for the next page, while text following the
display is used to fill the current page. (See also registers De
type is no indent; default
mode is no-fill.
rindent is the amount by which to shorten the line length in order
to bring text in from the right margin.
End display with .DE.
No indent (default).
Indent standard amount.
Center each line individually.
Center as a block.
No-fill mode (default).