Most windowing systems follow the independent overlapping windows approach, which emerged as an answer to the needs of the 80s' applications and technology. Advances in computers, display technology, and the applications demand more functionality from window management systems. Based on these changes and the problems of current windowing approaches, we have updated the requirements for multi-window systems to guide new methods of window management. We propose elastic windows with improved spatial layout and rapid multi-window operations. Multi-window operations are achieved by issuing operations on window groups hierarchically organized in a space-filling tiled layout. Sophisticated multi-window operations and spatial layout dynamics helps users to handle fast task-switching and to structure their work environment to their rapidly changing needs. We claim that these multi-window operations and the improved spatial layout decrease the cognitive load on users. Users found our prototype system to be comprehensible and enjoyable as they playfully explored the way multiple windows are reshaped.