What architectural feature helps transition between flat and rounded surfaces in Islamic architecture?

The transition between flat and rounded surfaces in Islamic architecture is effectively achieved through the use of muqarnas. This distinctive architectural element consists of a series of concave, multi-faceted forms that create a gradual transformation between different geometrical shapes.

Muqarnas are often used in vaults, domes, and ceilings, and they allow for a smooth and intricate transition from a square base to a dome or arched surface, making them particularly valuable in Islamic architectural design. This technique not only serves a practical purpose in structural transitions but also enhances the ornate aesthetic typical of Islamic art, reflecting the cultural emphasis on geometric and floral designs.

While the other options such as mosque domes, columns, and cupolas play significant roles in Islamic architecture, they do not specifically serve the function of bridging flat and rounded surfaces in the same manner that muqarnas do. This unique feature is integral to creating the harmonious and fluid shapes that characterize many Islamic structures.