Design sketch of a public lounge

Quick answer：

Design sketches of public lounges are detailed illustrations used to visualize and plan the layout, aesthetics, and functionality of communal areas designed for relaxation and socialization in public spaces such as offices, airports, or hotels. They typically include floor plans, furniture placement, color schemes, and decorative elements. These sketches are crucial for architects and designers to communicate their vision to clients and ensure the efficient use of space.