The viewer is encouraged to circumnavigate this large sculpture constructed of seven pieces of steel. The composition of its formal elements transforms when viewed from different vantage points. The work has no fixed visual identity, a plurality of configurations are simultaneously possible and valid.To keep the piece in harmony the individual elements are painted bright industrial pink. Caro selected this colour after the sculpture was finished and its identity established, to reinforce its mood. Caro uses applied colour to achieve a sense of weightlessness as it renders the surface of metal more optical than tactile. The fact that the central elements are a lighter shade of pink gives them an added suggestion of lift. Caro does not disguise Pink Stack’s engineering but nor does he puncture the illusion that gravity has been defied.Caro’s work does not emerge from a sketch or maquette but by directly experimenting with the placement of several forms, with no prior image in mind. Caro works close to the sculpture so that he does not edit it prematurely by applying preconceived notions of balance and composition. Once satisfied with the construction of his expressive abstract gestures, he welds the forms into position. His work is made in literal space, relating to the eye height of a standing person and cannot be enlarged or shrunk.During the 1950s Caro had been making figurative work modeled in clay or plaster and cast in bronze. In autumn 1959 he made a trip to America where conversation with Clement Greenberg and exposure to the sculpture of David Smith and paintings of Kenneth Noland triggered his conversion to abstraction. Caro turned to scrap steel, rejecting clay that bears the imprint of the artist’s hand and connotations of the human body. To distance himself from the figure, the totem and the monolith, Caro began to elongate his work. Length forced the sculptures to be read slowly, like a piece of music. Parodoxically, Caro felt he had was forced to make his sculpture abstract in order to make it more human.Caro