the shared user interface surface system is a simple and lightweight collaboration tool that is accessible simultaneously by multiple users through multiple sources . the shared user interface surface system provides a way to share a user interface surface and corresponding shared surface object , and coordinates local manipulations of respective local representations of the shared user interface surface and corresponding shared surface object , and updates the respective local representations with a group representation . the system accommodates diverse collaboration requirements including mixed written and spoken languages , utilization of the accessibility layer for physically disabled and disparate computing resources .