This is a simple steerable application and application-level steering
interface.  In this case, the application "ball" calculates the location of a
ball bouncing in a 2D box.  The ball's speed, direction. size and location are
represented by application-level objects.  Those objects are mirrored in the
program "gui/bounce".  This Motif-based program that allows the user to change
the direction, speed and size of the bouncing ball.  Any number of gui/bounce
programs may run concurrently, all mirroring the same application objects.
Changes made by one interface are reflected in the others.

To run, start "ball/ball" on some host.  Then run "gui/bounce" one or more
times, locally or remotely.  The bounce programs will locate each other based
on the rules in dataexchange/doc/group_services.3.  (If you run as different
users on different machines, set the COMM_GROUP_USER to some common ID.)
