Some of Rickey’s mobiles hang from the ceiling; others are grounded by three-legged, indeterminate forms. In many of them, thin intertwined wires branch out from a central spine, terminating in assorted shapes that serve as counterweights. These constructions clearly evidence the influence of Alexander Calder. In Four Last Leaves, completed in 1952, a slightly curved inner axis forms a thin line that is interrupted at various intervals by the twist of a joint where other wires attach. Minute flat circles attached to four of the elongated legs serve as delicately engineered balance points, lightly anchoring the structure and allowing the slightest air current to send the work crawling through the air.

from Kephart, Passages of Light and Time: George Rickey's Life in Motion (Notre Dame, 2009)