This refers to a design plan for a rooftop swimming pool that is not bounded by walls or other structures, providing an open, unconfined swimming experience. Rooftop pools are often seen in luxury hotels, high-end residential buildings, or as a unique feature in modern architectural design. They require careful planning for structural support, safety, and maintenance. The design of such a pool would include considerations for waterproofing, pool shape, access, and integration with the surrounding architecture.