I worked at Sun and had the ring. We had a great demo where you could walk along a row of Sun workstations, and your X session would move with you, leaping from monitor to monitor, keeping pace with you. The idea at the time was "The Network is the Computer".

IIRC there was some coding that enabled each workstation to know where it was physically, so the security systems could know "User is signed into workstation X, and is requesting a move from workstation X to workstation Y, which is physically one meter away, so AOK to keep signed in."