What type of furnishings are considered accessories in an architectural context?

In the context of architecture, accessories typically refer to items that enhance the aesthetic quality of a space without being essential or structurally integrated into its design. Art fits this definition as it is primarily decorative and serves the purpose of expressing creativity, culture, or identity within a built environment. It can include paintings, sculptures, installations, and other visual elements that contribute to the atmosphere and character of a space.

On the other hand, the other options listed involve functional elements that are integral to the use and layout of a space. Multiple seating refers to seating arrangements that accommodate groups of people and are essential for the function of social or communal areas. Casework refers to built-in furniture such as cabinets or shelves, which are functional components of a design. Site furniture includes items like benches or tables placed in exterior spaces, which also serve necessary roles for user comfort and outdoor usability. In contrast, art does not have a function beyond its decorative and expressive nature, solidifying its role as an accessory within architectural design.