gd input files may be nested, i.e. they may contain instructions to include other input files.
Inbedding is specified by the tag INBED: followed by the name of the file to be inbedded.
Example:

   INBED: plot7.gd
   INBED: plot8.gd
   INBED: plot9.gd

includes the files plot7.gd, plot8.gd and plot9.gd.

A possible application is the multiple use of a complicated combination of graphic elements:

   INBED: CHAMBER
   E: ROTATE(30)
   INBED: CHAMBER
   E: ROTATE(60)
   INBED: CHAMBER

The first line of an included file is assumed to contain the picture title and is ignored.
Multiple inbedding is possible, i.e. inbedded files may contain other inbedded files.
Self-inbedding is of course not allowed.