Along with Brazilian artists Amilcar de Castro, Franz Weissmann, Lygia Pape and poet Ferreira Gullar, Clark co-founded the Neo-Concrete movement.

[2][3] In 1938, she married Aluízio Clark Riberio, a civil engineer, and moved to Rio de Janeiro, where she gave birth to three children between 1941 and 1945.

[citation needed] Clark soon became a prime figure among the Neo-concretists, whose 1959 manifesto called for abstract art to be more subjective and less rational and idealist.

She drew on the writings of French philosopher Maurice Merleau-Ponty, whose phenomenology resonated with the intertwining of subject and object she sought in her breakthrough work of the 1960s.

These pieces addressed the simultaneous existence of opposites within the same space: internal and external, metaphorical and literal, male and female.

Art critic Guy Brett observed that Clark "produced many devices to dissolve the visual sense into an awareness of the body.

"[13] During the early part of Clark's career, she focused on creating small monochromatic paintings which were done in black, gray, and white.

Clark later moved on to co-found the Neo-Concrete movement, which fellow Brazilian artist Hélio Oiticica then joined.

[citation needed] In the late 1950s, Clark and some of her contemporaries broke away from the Concrete group to start the Neo-Concrete movement.

In Clark's writings, she articulates that an artwork should not be considered "a ‘machine’ nor an ‘object,’ but rather, an almost-body" which can only be made whole through viewer participation.

[17] Clark and Oiticica fused modern European geometric abstraction art with a Brazilian cultural flavor.

The Brazilian Neo-Concrete movement borrowed their artistic ideas from Max Bill who was the director of the Ulm School of Design in Germany during the early 1950s.

[18] They soon began making artworks the spectator could interact with physically, like Clark's Bichos (Critters), 1960–1963, which are ingenious arrangements of hinged metal plates that can fold flat, or be unfolded into three dimensions and manipulated into many different configurations.

[17] After the 1964 Brazilian coup d'état and the military dictatorship that took power in the fallout, a counterculture movement grew in response to the government's increasing scrutiny on the public.

At this point in time, Institutional Act Number Five was enacted and artists were forced into exile or fled the country out of fear of persecution.

"[22] She wanted to uncover why the power of certain objects brought about a vivid memory in her psychotherapy patients so that she could treat their psychosis.