Following a visit in October of 1930 to Piet Mondrian’s studio, where he was impressed by the environmental installation, Calder made his first wholly abstract compositions and invented the kinetic sculpture now known as the mobile. Coined for these works by Marcel Duchamp in 1931, the word “mobile” refers to both “motion” and “motive” in French. He also created stationary abstract works that Jean Arp dubbed “stabiles.”