Jean Arp’s transition from his painted wooden wall reliefs to his freestanding sculpture occurred about 1930. At this time he executed some freestanding reliefs, which rested either on carved bases or directly on the ground. Biomorphic elements like those attached to the wall reliefs gradually separated into independent forms and assumed positions in fully three-dimensional ensembles. When, in 1931, Arp began sculpting wood and modeling plaster in the round, he made figurative torsos. He next embarked on a series of abstract forms called Concretions, usually carved in plaster and some later cast in bronze, suggesting general processes of growth, crystallization, and metamorphosis, rather than specific motifs drawn from nature. Head and Shell shares the bulbous, protuberant character of the Concretions, its curved and coiled base expressing the spontaneous energy of pullulation. However, it is not one continuous form but two separable elements. Both conceptually and physically, this work is a unit composed of discrete parts. The object’s small size and its partite nature suggest that Arp intended the original plaster version to be handled. During the 1930s, the artist produced several small works made of multiple elements that the viewer could pick up, separate, and rearrange into new configurations.