From Britannica

Rocaille, in Western architecture and decorative arts, 18th-century style featuring elaborately stylized shell-like, rocklike, and scroll motifs. Rocaille is one of the more prominent aspects of the Rococo style of architecture and decoration that developed in France during the reign of King Louis XV (1715–74). The Rocaille style has been defined as a reaction both to the classic rigidity of the waning Baroque style and to the new interest in nature and the natural sciences. In French, rocaille means “rubble,” or “pebbles,” and style rocaille is synonymous with Rococo.

Rocaille is most often found in small pieces of furniture and household articles, especially in such personal items as snuffboxes and hand mirrors. In wall decorations of wood or plaster, rocaille features shells, pebbles, and scrolls as well as flower, fern, and coral forms, all emphasizing brief, asymmetric single or double curves. Originally the term was confined to the fanciful pierced shellwork of artificial grottoes in late Renaissance gardens.

Just like how the Ottoman miniature style informed the art direction of The Carpet Merchant’s Vol I, the Rococo style will be a major part of the visual look of Chapter 4 (it’s not the only style – there will be some early Neoclassism, and lots of Turquerie).