* demo1-create.rb	a basic test of file creation.
			creates a file and prints its contents.
* demo1-create-alt.rb	an alternative way to write demo1-create.rb
* demo2-graphic.rb	creates a file and close it. Then reopens and
			visualize it using AdvancedDCL
			(AdvancedDCL at http://www.gfd-dennou.org/arch/ruby/
			must have been installed)

* demo3-ncepclim.rb	plots arbitrary 2D slices the 4D distribution of
			global temperature climatology from
			the NCEP reanalysis data. The data (8MB) is downloaded
			by anonymous ftp if not found in the user's
			run-time directory and he or she wants it.