Clearboard works well as long as the only shared objects the two users care about are the ones drawn on the whiteboard. What if they want to refer to both the physical objects on the distributed desktops and electronic objects created by computer applications. We can display these objects in separate windows or screens, but that forces a user to focus on one set of objects at a time. TeamWorkstation [], instead, creates a seamless environment in which the two sets of objects are overlaid on a single shared display.
TeamWorkstation uses the CaptureLab [] approach of sharing a single cpu (running a single set of applications) between the local and remote displays. It captures all video signals sent by the cpu to its local display and sends them over the network to the remote display. It also send images of each desktop captured by a video camera to the other site, where it is mixed with the cpu-generated stream to create the overlay. Finally, to support multiuser input, it captures the keyboard events generated by the remote user and sends it over the network to the local site, where it is multiplexed with the keyboard events of the local user before being delivered to the applications.