IDEMO:
------

1. start IDL

    example % idl
    IDL. Version 3.0.0 (sunos sparc).
    Copyright 1989-1992, Research Systems, Inc.
    All rights reserved.  Unauthorized reproduction prohibited.
    Site: 1341.
    Licensed for use by: Universitaet Dortmund

    20 March 1992
        The file openwin3.doc in the notes directory of the IDL
        distribution describes how to solve the following problems:
            - How to prevent IDL from complaining about missing fonts
              when running an X Server other than OpenWindows.  
            - How to prevent IDL from complaining about missing bitmap
              files for widgets.
            - Running IDL 2.2.3 or newer requires the system manager
              to install an X Window system applications default file
              for IDL before widgets will behave properly.
            - How to prevent "Cannot allocate colormap entry" errors.

    If you are tired of seeing this message, edit or delete the
    file motd_sunos, in the main IDL directory.
    IDL>

2. compile procedure `hodge'

    IDL> .run hodge

3. plot data in mode 0..3

    IDL> pl,3
