[Xy-pic] using a tar archive

[Michael Barr]

If Ross insists on distributing tar archives, perhaps he could add some 
instructions on how to extract them.  I have downloaded xymods.tgz, 
gunzipped it, read the tar man carefully and run
tar -x xymods.tar
and the computer simply hangs until I do ctl-C.  I guess it wants 
something else, but I sure cannot guess what and the man page is no help.  
Why can't you use zip/unzip that is perfectly simple?