This is among the earliest of Calder's hanging mobiles. Calder made frequent trips to Paris where he was friendly with the Surrealists. The poetic, floating forms of this mobile look like three-dimensional equivalents of Miró's paintings. It has been suggested that they have a source in scientific models of the planetary system. Arp's sculptures were also an influence on Calder. Due to his training as an engineer, Calder was well acquainted with the mechanical principles required to make his mobiles balance and move freely.