An homage to the geometries of art
Even in the historic avant-garde's use of geometric shapes as the new language of abstract art, the circle is described as an extremely complex element: a shape that is precise and yet inexhaustibly variable; both stable and unstable at the same time. It has a tension to it that holds infinite other tensions—a synthesis of great contrasts, united in an equilibrium of the concentric and the eccentric.
In its complexity, the circle suggests a curve—another shape that has always been used in the arts. The arc, for example, was first "invented" by the Etruscans and was then borrowed from them by the Romans. Just like the circle, the curve also has its roots in the morphology of organisms, animals, and plants.
The curved, elegant, and flowing lines that dominate Gothic art are also prominent in the Baroque style, which draws on the dynamism, plasticity, and rhythm of generally curvilinear—and often polycentric—structures. While the circle has no beginning or end, the curve, as part of the circle, can insinuate a direction and orientation, and can also imply movement.
Futurists explored the curve's underlying dynamism, while Art Nouveau adopted an undulating line known as the "whiplash curve" to bring attention to the vital force of nature, explaining it in spiritual and symbolic terms. Both the circle and the curve are crucial elements of the "design" art of the 1950s and 1960s, spatialist and minimalist works, and the most recent examples of the conceptual.