DEFLOOP -- Lists, saves and restores loops
  DEFLOOP LIST bloop eloop
  DEFLOOP SAVE loop "label
  DEFLOOP REST loop
Parameter:
  LIST | lists saved loops
  SAVE | saves the current loop
  REST | restores a previously saved loop
  bloop | beginning loop to list (def=all defined loops)
  eloop | ending loop to list (def=bloop)
  loop | loop number to save or restore; the range is 1-99
  "label | label to be saved with the loop; 48 characters maximum
           including blanks
Remarks:
  The SAVE option saves the current loop settings (looping on/off,
  frame sequence, dwell rates, cursor position, image on/off and
  graphic on/off). The REST option restores the loop (with the saved
  loop settings) to the main display.

  You can restore loops 1-9 to briefing window created with the BRIEF
  command). All the loop settings except the cursor position, image
  on/off and graphic on/off are restored. To restore the loop to a
  briefing window, use the MOVIE command with the WIN keyword, or make
  the briefing window active and press the keyboard key between 1 and 9
  that corresponds to the loop number between 1 and 9. Press L to
  manually start or stop looping, A to advance a frame, and B to back
  up a frame in the loop.

  Note that 16K bytes are required on disk to store the context for
  a loop.  You should, therefore, always add new loops consecutively
  in order to save disk space.
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